diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 2d966037..da49ea75 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -28,7 +28,7 @@ jobs:
           # Note: Specifying the version of valgrind and wasm-pack is not supported.
           # cargo-watch is supported by cargo-binstall (through quickinstall)
           - cargo-hack,cargo-llvm-cov,cargo-minimal-versions,parse-changelog,cross,nextest,shellcheck,shfmt,valgrind,wasm-pack,wasmtime,mdbook,cargo-watch
-          - cargo-hack@0.5.14,cargo-llvm-cov@0.4.8,cargo-minimal-versions@0.1.4,parse-changelog@0.4.8,cross@0.2.1,nextest@0.9.11,shellcheck@0.8.0,shfmt@3.5.1,wasmtime@0.38.1,mdbook@0.4.18,cargo-watch@8.1.1
+          - cargo-hack@0.5.14,cargo-llvm-cov@0.4.8,cargo-minimal-versions@0.1.4,parse-changelog@0.4.8,cross@0.2.1,nextest@0.9.11,shellcheck@0.8.0,shfmt@3.5.1,wasmtime@0.38.1,mdbook@0.4.19,cargo-watch@8.1.1
           # Nextest supports basic version ranges as well
           - nextest@0.9
         include:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index c9cde025..83174f6e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,8 @@ Note: In this file, do not use the hard wrap in the middle of a sentence for com
 
 ## [Unreleased]
 
+- Update `mdbook@latest` to 0.4.19.
+
 ## [1.5.0] - 2022-06-28
 
 - Enable secure mode for `cargo-binstall`. ([#9](https://github.com/taiki-e/install-action/pull/9), thanks @NobodyXu)
diff --git a/main.sh b/main.sh
index c4710424..07f1ba2d 100755
--- a/main.sh
+++ b/main.sh
@@ -266,7 +266,7 @@ for tool in "${tools[@]}"; do
             ;;
         mdbook)
             # https://github.com/rust-lang/mdBook/releases
-            latest_version="0.4.18"
+            latest_version="0.4.19"
             repo="rust-lang/mdBook"
             case "${OSTYPE}" in
                 linux*) target="x86_64-unknown-linux-gnu" ;;