diff --git a/class.go b/class.go
index eabd13b..b4d429d 100644
--- a/class.go
+++ b/class.go
@@ -27,6 +27,8 @@ func (mrb *State) ClassOf(v Value) *RClass {
 		if v == false {
 			return mrb.falseClass
 		}
+
+		return mrb.trueClass
 	}
 
 	return nil
diff --git a/mruby.go b/mruby.go
index afb4fc6..818f29d 100644
--- a/mruby.go
+++ b/mruby.go
@@ -1,8 +1,6 @@
 package mruby
 
 import (
-	"fmt"
-
 	"github.com/elct9620/mruby-go/stack"
 )
 
@@ -29,6 +27,7 @@ type State struct {
 	context *context
 
 	falseClass  *RClass
+	trueClass   *RClass
 	objectClass *RClass
 
 	topSelf *RObject
@@ -39,7 +38,6 @@ func New() *State {
 		context: &context{
 			callinfo: stack.New[*callinfo](),
 		},
-		falseClass:  NewClass(),
 		objectClass: NewClass(),
 		topSelf:     &RObject{},
 	}
@@ -62,11 +60,5 @@ func (s *State) GetArgv() []Value {
 }
 
 func initCore(mrb *State) {
-	mrb.objectClass.DefineMethod("puts", &Method{
-		Function: func(mrb *State, recv Value) Value {
-			args := mrb.GetArgv()
-			fmt.Println(args...)
-			return args[0]
-		},
-	})
+	initObject(mrb)
 }
diff --git a/object.go b/object.go
index 58b385f..2e47cf9 100644
--- a/object.go
+++ b/object.go
@@ -1,8 +1,23 @@
 package mruby
 
+import "fmt"
+
 type RBasic struct {
 }
 
 type RObject struct {
 	RBasic
 }
+
+func initObject(mrb *State) {
+	mrb.falseClass = NewClass()
+	mrb.trueClass = NewClass()
+
+	mrb.objectClass.DefineMethod("puts", &Method{
+		Function: func(mrb *State, recv Value) Value {
+			args := mrb.GetArgv()
+			fmt.Println(args...)
+			return args[0]
+		},
+	})
+}