diff --git a/doc/irb/irb.rd.ja b/doc/irb/irb.rd.ja
index 633c08cbd..c51e0bd60 100644
--- a/doc/irb/irb.rd.ja
+++ b/doc/irb/irb.rd.ja
@@ -125,7 +125,6 @@ irb起動時に``~/.irbrc''を読み込みます. もし存在しない場合は
 
    IRB.conf[:PROMPT][:MY_PROMPT] = { # プロンプトモードの名前
      :PROMPT_I => nil,		  # 通常のプロンプト
-     :PROMPT_N => nil,		  # 継続行のプロンプト
      :PROMPT_S => nil,		  # 文字列などの継続行のプロンプト
      :PROMPT_C => nil,		  # 式が継続している時のプロンプト
      :RETURN => "    ==>%s\n"	  # リターン時のプロンプト
@@ -140,7 +139,7 @@ OKです.
 
   IRB.conf[:PROMPT_MODE] = :MY_PROMPT
 
-PROMPT_I, PROMPT_N, PROMPT_S, PROMPT_Cは, フォーマットを指定します.
+PROMPT_I, PROMPT_S, PROMPT_Cは, フォーマットを指定します.
 
   %N	起動しているコマンド名が出力される.
   %m	mainオブジェクト(self)がto_sで出力される.
@@ -155,7 +154,6 @@ PROMPT_I, PROMPT_N, PROMPT_S, PROMPT_Cは, フォーマットを指定します.
 
   IRB.conf[:PROMPT][:DEFAULT] = {
       :PROMPT_I => "%N(%m):%03n:%i> ",
-      :PROMPT_N => "%N(%m):%03n:%i> ",
       :PROMPT_S => "%N(%m):%03n:%i%l ",
       :PROMPT_C => "%N(%m):%03n:%i* ",
       :RETURN => "=> %s\n"
diff --git a/lib/irb.rb b/lib/irb.rb
index 93ab6370e..617e4a46c 100644
--- a/lib/irb.rb
+++ b/lib/irb.rb
@@ -196,7 +196,6 @@
 #
 #     IRB.conf[:PROMPT_MODE][:DEFAULT] = {
 #       :PROMPT_I => "%N(%m):%03n> ",
-#       :PROMPT_N => "%N(%m):%03n> ",
 #       :PROMPT_S => "%N(%m):%03n%l ",
 #       :PROMPT_C => "%N(%m):%03n* ",
 #       :RETURN => "%s\n" # used to printf
@@ -206,35 +205,30 @@
 #
 #   # :NULL:
 #   #   :PROMPT_I:
-#   #   :PROMPT_N:
 #   #   :PROMPT_S:
 #   #   :PROMPT_C:
 #   #   :RETURN: |
 #   #     %s
 #   # :DEFAULT:
 #   #   :PROMPT_I: ! '%N(%m):%03n> '
-#   #   :PROMPT_N: ! '%N(%m):%03n> '
 #   #   :PROMPT_S: ! '%N(%m):%03n%l '
 #   #   :PROMPT_C: ! '%N(%m):%03n* '
 #   #   :RETURN: |
 #   #     => %s
 #   # :CLASSIC:
 #   #   :PROMPT_I: ! '%N(%m):%03n:%i> '
-#   #   :PROMPT_N: ! '%N(%m):%03n:%i> '
 #   #   :PROMPT_S: ! '%N(%m):%03n:%i%l '
 #   #   :PROMPT_C: ! '%N(%m):%03n:%i* '
 #   #   :RETURN: |
 #   #     %s
 #   # :SIMPLE:
 #   #   :PROMPT_I: ! '>> '
-#   #   :PROMPT_N: ! '>> '
 #   #   :PROMPT_S:
 #   #   :PROMPT_C: ! '?> '
 #   #   :RETURN: |
 #   #     => %s
 #   # :INF_RUBY:
 #   #   :PROMPT_I: ! '%N(%m):%03n> '
-#   #   :PROMPT_N:
 #   #   :PROMPT_S:
 #   #   :PROMPT_C:
 #   #   :RETURN: |
@@ -242,7 +236,6 @@
 #   #   :AUTO_INDENT: true
 #   # :XMP:
 #   #   :PROMPT_I:
-#   #   :PROMPT_N:
 #   #   :PROMPT_S:
 #   #   :PROMPT_C:
 #   #   :RETURN: |2
@@ -527,8 +520,6 @@ def eval_input
           f = @context.prompt_s
         elsif continue
           f = @context.prompt_c
-        elsif indent > 0
-          f = @context.prompt_n
         else
           f = @context.prompt_i
         end
diff --git a/lib/irb/context.rb b/lib/irb/context.rb
index 43d9b5343..6d6261e60 100644
--- a/lib/irb/context.rb
+++ b/lib/irb/context.rb
@@ -229,8 +229,6 @@ def main
     #
     # See IRB@Customizing+the+IRB+Prompt for more information.
     attr_accessor :prompt_c
-    # See IRB@Customizing+the+IRB+Prompt for more information.
-    attr_accessor :prompt_n
     # Can be either the default <code>IRB.conf[:AUTO_INDENT]</code>, or the
     # mode set by #prompt_mode=
     #
@@ -414,7 +412,6 @@ def prompt_mode=(mode)
       @prompt_i = pconf[:PROMPT_I]
       @prompt_s = pconf[:PROMPT_S]
       @prompt_c = pconf[:PROMPT_C]
-      @prompt_n = pconf[:PROMPT_N]
       @return_format = pconf[:RETURN]
       @return_format = "%s\n" if @return_format == nil
       if ai = pconf.include?(:AUTO_INDENT)
diff --git a/lib/irb/init.rb b/lib/irb/init.rb
index ef07a5f1e..d1097b573 100644
--- a/lib/irb/init.rb
+++ b/lib/irb/init.rb
@@ -58,35 +58,30 @@ def IRB.init_config(ap_path)
     @CONF[:PROMPT] = {
       :NULL => {
         :PROMPT_I => nil,
-        :PROMPT_N => nil,
         :PROMPT_S => nil,
         :PROMPT_C => nil,
         :RETURN => "%s\n"
       },
       :DEFAULT => {
         :PROMPT_I => "%N(%m):%03n> ",
-        :PROMPT_N => "%N(%m):%03n> ",
         :PROMPT_S => "%N(%m):%03n%l ",
         :PROMPT_C => "%N(%m):%03n* ",
         :RETURN => "=> %s\n"
       },
       :CLASSIC => {
         :PROMPT_I => "%N(%m):%03n:%i> ",
-        :PROMPT_N => "%N(%m):%03n:%i> ",
         :PROMPT_S => "%N(%m):%03n:%i%l ",
         :PROMPT_C => "%N(%m):%03n:%i* ",
         :RETURN => "%s\n"
       },
       :SIMPLE => {
         :PROMPT_I => ">> ",
-        :PROMPT_N => ">> ",
         :PROMPT_S => "%l> ",
         :PROMPT_C => "?> ",
         :RETURN => "=> %s\n"
       },
       :INF_RUBY => {
         :PROMPT_I => "%N(%m):%03n> ",
-        :PROMPT_N => nil,
         :PROMPT_S => nil,
         :PROMPT_C => nil,
         :RETURN => "%s\n",
@@ -94,7 +89,6 @@ def IRB.init_config(ap_path)
       },
       :XMP => {
         :PROMPT_I => nil,
-        :PROMPT_N => nil,
         :PROMPT_S => nil,
         :PROMPT_C => nil,
         :RETURN => "    ==>%s\n"
diff --git a/test/irb/test_cmd.rb b/test/irb/test_cmd.rb
index dcea020b1..74a8ab3a0 100644
--- a/test/irb/test_cmd.rb
+++ b/test/irb/test_cmd.rb
@@ -228,8 +228,7 @@ def test_measure
           DEFAULT: {
             PROMPT_I: '> ',
             PROMPT_S: '> ',
-            PROMPT_C: '> ',
-            PROMPT_N: '> '
+            PROMPT_C: '> '
           }
         },
         PROMPT_MODE: :DEFAULT,
@@ -258,8 +257,7 @@ def test_measure_keeps_previous_value
           DEFAULT: {
             PROMPT_I: '> ',
             PROMPT_S: '> ',
-            PROMPT_C: '> ',
-            PROMPT_N: '> '
+            PROMPT_C: '> '
           }
         },
         PROMPT_MODE: :DEFAULT,
@@ -286,8 +284,7 @@ def test_measure_enabled_by_rc
           DEFAULT: {
             PROMPT_I: '> ',
             PROMPT_S: '> ',
-            PROMPT_C: '> ',
-            PROMPT_N: '> '
+            PROMPT_C: '> '
           }
         },
         PROMPT_MODE: :DEFAULT,
@@ -317,8 +314,7 @@ def test_measure_enabled_by_rc_with_custom
           DEFAULT: {
             PROMPT_I: '> ',
             PROMPT_S: '> ',
-            PROMPT_C: '> ',
-            PROMPT_N: '> '
+            PROMPT_C: '> '
           }
         },
         PROMPT_MODE: :DEFAULT,
@@ -348,8 +344,7 @@ def test_measure_with_custom
           DEFAULT: {
             PROMPT_I: '> ',
             PROMPT_S: '> ',
-            PROMPT_C: '> ',
-            PROMPT_N: '> '
+            PROMPT_C: '> '
           }
         },
         PROMPT_MODE: :DEFAULT,
@@ -375,8 +370,7 @@ def test_measure_with_proc
           DEFAULT: {
             PROMPT_I: '> ',
             PROMPT_S: '> ',
-            PROMPT_C: '> ',
-            PROMPT_N: '> '
+            PROMPT_C: '> '
           }
         },
         PROMPT_MODE: :DEFAULT,
diff --git a/test/irb/test_context.rb b/test/irb/test_context.rb
index 5847df172..29c67392f 100644
--- a/test/irb/test_context.rb
+++ b/test/irb/test_context.rb
@@ -454,7 +454,6 @@ def main.inspect
     def test_default_return_format
       IRB.conf[:PROMPT][:MY_PROMPT] = {
         :PROMPT_I => "%03n> ",
-        :PROMPT_N => "%03n> ",
         :PROMPT_S => "%03n> ",
         :PROMPT_C => "%03n> "
         # without :RETURN
diff --git a/test/irb/yamatanooroti/test_rendering.rb b/test/irb/yamatanooroti/test_rendering.rb
index 6da7fded2..c094111fb 100644
--- a/test/irb/yamatanooroti/test_rendering.rb
+++ b/test/irb/yamatanooroti/test_rendering.rb
@@ -179,7 +179,6 @@ def test_autocomplete_with_showdoc_in_gaps_on_narrow_screen_right
     write_irbrc <<~'LINES'
       IRB.conf[:PROMPT][:MY_PROMPT] = {
         :PROMPT_I => "%03n> ",
-        :PROMPT_N => "%03n> ",
         :PROMPT_S => "%03n> ",
         :PROMPT_C => "%03n> "
       }
@@ -214,7 +213,6 @@ def test_autocomplete_with_showdoc_in_gaps_on_narrow_screen_left
     write_irbrc <<~'LINES'
       IRB.conf[:PROMPT][:MY_PROMPT] = {
         :PROMPT_I => "%03n> ",
-        :PROMPT_N => "%03n> ",
         :PROMPT_S => "%03n> ",
         :PROMPT_C => "%03n> "
       }