diff --git a/package.json b/package.json
index b29317a..613cb09 100644
--- a/package.json
+++ b/package.json
@@ -28,6 +28,7 @@
     "react-syntax-highlighter": "^15.4.5",
     "recoil": "^0.5.2",
     "recoil-persist": "^4.0.0",
+    "refractor": "3",
     "remark-gfm": "^3.0.1"
   },
   "devDependencies": {
@@ -37,6 +38,7 @@
     "@types/react": "17.0.37",
     "@types/react-syntax-highlighter": "^13.5.2",
     "@types/recoil": "^0.0.9",
+    "@types/refractor": "^3.0.2",
     "eslint": "7",
     "eslint-config-next": "^12.0.4",
     "eslint-config-prettier": "^8.3.0",
diff --git a/src/components/review/DiffRenderer.tsx b/src/components/review/DiffRenderer.tsx
index 1674870..4005e18 100644
--- a/src/components/review/DiffRenderer.tsx
+++ b/src/components/review/DiffRenderer.tsx
@@ -1,6 +1,9 @@
+import path from "path";
+
 import { PlusSquareIcon } from "@chakra-ui/icons";
 import { Box } from "@chakra-ui/react";
 import { useMemo, useState } from "react";
+import refractor from "refractor";
 
 import ReviewPopover from "@/components/review/Popover";
 
@@ -9,6 +12,7 @@ const Diff = reactDiffView.Diff;
 const Hunk = reactDiffView.Hunk;
 const Decoration = reactDiffView.Decoration;
 const getChangeKey = reactDiffView.getChangeKey;
+const tokenize = reactDiffView.tokenize;
 
 type Props = {
   fileId: string;
@@ -43,6 +47,22 @@ const DiffRenderer = ({
   const [tmpChangeKey, setTmpChangeKey] = useState<string>("");
   const postPath: string = type === "delete" ? oldPath : newPath;
 
+  const tokens = useMemo(() => {
+    try {
+      return tokenize(hunks, {
+        highlight: true,
+        refractor: refractor,
+        language: path.extname(postPath).slice(1),
+      });
+    } catch (e) {
+      // ・ファイル名の文字列 (postPath) が空文字の可能性のある初回ロード
+      // ・ライブラリ非対応の拡張子
+      // の場合、refractor ライブラリがエラーを送出するので
+      // シンタックスハイライトを無効にする
+      return tokenize(hunks, { highlight: false });
+    }
+  }, [hunks]);
+
   const renderGutter = ({
     side,
     renderDefault,
@@ -76,6 +96,7 @@ const DiffRenderer = ({
       viewType="unified"
       diffType={type}
       hunks={hunks}
+      tokens={tokens}
       widgets={widgets[fileId]}
       renderGutter={renderGutter}
     >
diff --git a/src/pages/_app.tsx b/src/pages/_app.tsx
index 4fae16e..b6dddd8 100644
--- a/src/pages/_app.tsx
+++ b/src/pages/_app.tsx
@@ -5,6 +5,8 @@ import Head from "next/head";
 import { RecoilRoot } from "recoil";
 
 import { AuthProvider } from "@/components/AuthProvider";
+
+import "prismjs/themes/prism.css";
 import "@/style/difffile.css";
 
 const MyApp: NextPage<AppProps> = ({ Component, pageProps }) => {
diff --git a/yarn.lock b/yarn.lock
index 0bede10..f0adea5 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2178,6 +2178,11 @@
   resolved "https://registry.yarnpkg.com/@types/prettier/-/prettier-2.4.3.tgz#a3c65525b91fca7da00ab1a3ac2b5a2a4afbffbf"
   integrity sha512-QzSuZMBuG5u8HqYz01qtMdg/Jfctlnvj1z/lYnIDXs/golxw0fxtRAHd9KrzjR7Yxz1qVeI00o0kiO3PmVdJ9w==
 
+"@types/prismjs@*":
+  version "1.26.0"
+  resolved "https://registry.yarnpkg.com/@types/prismjs/-/prismjs-1.26.0.tgz#a1c3809b0ad61c62cac6d4e0c56d610c910b7654"
+  integrity sha512-ZTaqn/qSqUuAq1YwvOFQfVW1AR/oQJlLSZVustdjwI+GZ8kr0MSHBj0tsXPW1EqHubx50gtBEjbPGsdZwQwCjQ==
+
 "@types/prop-types@*":
   version "15.7.4"
   resolved "https://registry.yarnpkg.com/@types/prop-types/-/prop-types-15.7.4.tgz#fcf7205c25dff795ee79af1e30da2c9790808f11"
@@ -2206,6 +2211,13 @@
   dependencies:
     recoil "*"
 
+"@types/refractor@^3.0.2":
+  version "3.0.2"
+  resolved "https://registry.yarnpkg.com/@types/refractor/-/refractor-3.0.2.tgz#2d42128d59f78f84d2c799ffc5ab5cadbcba2d82"
+  integrity sha512-2HMXuwGuOqzUG+KUTm9GDJCHl0LCBKsB5cg28ujEmVi/0qgTb6jOmkVSO5K48qXksyl2Fr3C0Q2VrgD4zbwyXg==
+  dependencies:
+    "@types/prismjs" "*"
+
 "@types/scheduler@*":
   version "0.16.2"
   resolved "https://registry.yarnpkg.com/@types/scheduler/-/scheduler-0.16.2.tgz#1a62f89525723dde24ba1b01b092bf5df8ad4d39"
@@ -6390,6 +6402,11 @@ prismjs@^1.25.0, prismjs@~1.25.0:
   resolved "https://registry.yarnpkg.com/prismjs/-/prismjs-1.25.0.tgz#6f822df1bdad965734b310b315a23315cf999756"
   integrity sha512-WCjJHl1KEWbnkQom1+SzftbtXMKQoezOCYs5rECqMN+jP+apI7ftoflyqigqzopSO3hMhTEb0mFClA8lkolgEg==
 
+prismjs@~1.27.0:
+  version "1.27.0"
+  resolved "https://registry.yarnpkg.com/prismjs/-/prismjs-1.27.0.tgz#bb6ee3138a0b438a3653dd4d6ce0cc6510a45057"
+  integrity sha512-t13BGPUlFDR7wRB5kQDG4jjl7XeuH6jbJGt11JHPL96qwsEHNX2+68tFXqc1/k+/jALsbSWJKUOT/hcYAZ5LkA==
+
 process-nextick-args@~2.0.0:
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/process-nextick-args/-/process-nextick-args-2.0.1.tgz#7820d9b16120cc55ca9ae7792680ae7dba6d7fe2"
@@ -6716,6 +6733,15 @@ redent@^3.0.0:
     indent-string "^4.0.0"
     strip-indent "^3.0.0"
 
+refractor@3:
+  version "3.6.0"
+  resolved "https://registry.yarnpkg.com/refractor/-/refractor-3.6.0.tgz#ac318f5a0715ead790fcfb0c71f4dd83d977935a"
+  integrity sha512-MY9W41IOWxxk31o+YvFCNyNzdkc9M20NoZK5vq6jkv4I/uh2zkWcfudj0Q1fovjUQJrNewS9NMzeTtqPf+n5EA==
+  dependencies:
+    hastscript "^6.0.0"
+    parse-entities "^2.0.0"
+    prismjs "~1.27.0"
+
 refractor@^3.2.0:
   version "3.5.0"
   resolved "https://registry.yarnpkg.com/refractor/-/refractor-3.5.0.tgz#334586f352dda4beaf354099b48c2d18e0819aec"