diff --git a/internal/terraform/plan.go b/internal/terraform/plan.go
index 68cce4b..7edfc65 100644
--- a/internal/terraform/plan.go
+++ b/internal/terraform/plan.go
@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"strings"
 	"text/template"
 
 	tfjson "github.com/hashicorp/terraform-json"
@@ -57,15 +58,18 @@ func (r ResourceChangeData) GetUnifiedDiffString() (string, error) {
 	if err != nil {
 		return "", fmt.Errorf("invalid resource changes (after) : %w", err)
 	}
+	// Try to parse JSON string in values
+	replacer := strings.NewReplacer(`\n`, "\n  ", `\"`, "\"")
 	diff := difflib.UnifiedDiff{
-		A:       difflib.SplitLines(string(before)),
-		B:       difflib.SplitLines(string(after)),
+		A:       difflib.SplitLines(replacer.Replace(string(before))),
+		B:       difflib.SplitLines(replacer.Replace(string(after))),
 		Context: 3,
 	}
 	diffText, err := difflib.GetUnifiedDiffString(diff)
 	if err != nil {
 		return "", fmt.Errorf("failed to create diff: %w", err)
 	}
+
 	return diffText, nil
 }
 
diff --git a/internal/terraform/plan_test.go b/internal/terraform/plan_test.go
index 5d16e2c..f663ceb 100644
--- a/internal/terraform/plan_test.go
+++ b/internal/terraform/plan_test.go
@@ -23,6 +23,7 @@ func Test_newPlanData(t *testing.T) {
 		{name: "single_replace", wantErr: false},
 		{name: "all_types_mixed", wantErr: false},
 		{name: "aws_sample", wantErr: false},
+		{name: "iam_policy", wantErr: false},
 		{name: "invalid_json", wantErr: true},
 		{name: "not_json", wantErr: true},
 	}
@@ -56,6 +57,7 @@ func Test_render(t *testing.T) {
 		{name: "single_replace", wantErr: false},
 		{name: "all_types_mixed", wantErr: false},
 		{name: "aws_sample", wantErr: false},
+		{name: "iam_policy", wantErr: false},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
diff --git a/test/testdata/iam_policy/expected.md b/test/testdata/iam_policy/expected.md
new file mode 100644
index 0000000..6eac833
--- /dev/null
+++ b/test/testdata/iam_policy/expected.md
@@ -0,0 +1,20 @@
+### 0 to add, 1 to change, 0 to destroy, 0 to replace.
+- change
+    - aws_iam_policy.test_policy
+<details><summary>Change details</summary>
+
+```diff
+# aws_iam_policy.test_policy will be updated in-place
+@@ -12,7 +12,8 @@
+       "Action": [
+         "autoscaling:Describe*",
+         "ec2:Describe*",
+-        "elasticloadbalancing:Describe*"
++        "elasticloadbalancing:Describe*",
++        "health:Describe*"
+       ],
+       "Resource": "*"
+     }
+```
+
+</details>
diff --git a/test/testdata/iam_policy/show.json b/test/testdata/iam_policy/show.json
new file mode 100644
index 0000000..54493d9
--- /dev/null
+++ b/test/testdata/iam_policy/show.json
@@ -0,0 +1 @@
+{"format_version":"1.0","terraform_version":"1.1.8","planned_values":{"root_module":{"resources":[{"address":"aws_iam_policy.test_policy","mode":"managed","type":"aws_iam_policy","name":"test_policy","provider_name":"registry.terraform.io/hashicorp/aws","schema_version":0,"values":{"arn":"arn:aws:iam::363188159740:policy/test_policy","description":"","id":"arn:aws:iam::363188159740:policy/test_policy","name":"test_policy","name_prefix":null,"path":"/","policy":"{\n  \"Version\": \"2012-10-17\",\n  \"Statement\": {\n    \"Effect\": \"Allow\",\n    \"Action\": [\n      \"autoscaling:Describe*\",\n      \"ec2:Describe*\",\n      \"elasticloadbalancing:Describe*\",\n      \"health:Describe*\"\n    ],\n    \"Resource\": \"*\"\n  }\n}\n"},"sensitive_values":{}}]}},"resource_changes":[{"address":"aws_iam_policy.test_policy","mode":"managed","type":"aws_iam_policy","name":"test_policy","provider_name":"registry.terraform.io/hashicorp/aws","change":{"actions":["update"],"before":{"arn":"arn:aws:iam::363188159740:policy/test_policy","description":"","id":"arn:aws:iam::363188159740:policy/test_policy","name":"test_policy","name_prefix":null,"path":"/","policy":"{\n  \"Version\": \"2012-10-17\",\n  \"Statement\": {\n    \"Effect\": \"Allow\",\n    \"Action\": [\n      \"autoscaling:Describe*\",\n      \"ec2:Describe*\",\n      \"elasticloadbalancing:Describe*\"\n    ],\n    \"Resource\": \"*\"\n  }\n}\n"},"after":{"arn":"arn:aws:iam::363188159740:policy/test_policy","description":"","id":"arn:aws:iam::363188159740:policy/test_policy","name":"test_policy","name_prefix":null,"path":"/","policy":"{\n  \"Version\": \"2012-10-17\",\n  \"Statement\": {\n    \"Effect\": \"Allow\",\n    \"Action\": [\n      \"autoscaling:Describe*\",\n      \"ec2:Describe*\",\n      \"elasticloadbalancing:Describe*\",\n      \"health:Describe*\"\n    ],\n    \"Resource\": \"*\"\n  }\n}\n"},"after_unknown":{},"before_sensitive":{},"after_sensitive":{}}}],"prior_state":{"format_version":"1.0","terraform_version":"1.1.8","values":{"root_module":{"resources":[{"address":"aws_iam_policy.test_policy","mode":"managed","type":"aws_iam_policy","name":"test_policy","provider_name":"registry.terraform.io/hashicorp/aws","schema_version":0,"values":{"arn":"arn:aws:iam::363188159740:policy/test_policy","description":"","id":"arn:aws:iam::363188159740:policy/test_policy","name":"test_policy","name_prefix":null,"path":"/","policy":"{\n  \"Version\": \"2012-10-17\",\n  \"Statement\": {\n    \"Effect\": \"Allow\",\n    \"Action\": [\n      \"autoscaling:Describe*\",\n      \"ec2:Describe*\",\n      \"elasticloadbalancing:Describe*\"\n    ],\n    \"Resource\": \"*\"\n  }\n}\n"},"sensitive_values":{}}]}}},"configuration":{"provider_config":{"aws":{"name":"aws","expressions":{"region":{"constant_value":"ap-northeast-1"}}}},"root_module":{"resources":[{"address":"aws_iam_policy.test_policy","mode":"managed","type":"aws_iam_policy","name":"test_policy","provider_config_key":"aws","expressions":{"name":{"constant_value":"test_policy"},"policy":{"constant_value":"{\n  \"Version\": \"2012-10-17\",\n  \"Statement\": {\n    \"Effect\": \"Allow\",\n    \"Action\": [\n      \"autoscaling:Describe*\",\n      \"ec2:Describe*\",\n      \"elasticloadbalancing:Describe*\",\n      \"health:Describe*\"\n    ],\n    \"Resource\": \"*\"\n  }\n}\n"}},"schema_version":0}]}}}