diff --git a/.envrc b/.envrc
index 22bd8064..197c0d59 100644
--- a/.envrc
+++ b/.envrc
@@ -1,2 +1,3 @@
-use_nix
+#!/bin/bash
 
+use flake
diff --git a/.github/workflows/ci-home.yml b/.github/workflows/ci-home.yml
index 2a018670..fdc5ba3c 100644
--- a/.github/workflows/ci-home.yml
+++ b/.github/workflows/ci-home.yml
@@ -34,8 +34,6 @@ jobs:
     steps:
       - uses: DeterminateSystems/nix-installer-action@v4
       - uses: DeterminateSystems/magic-nix-cache-action@v2
-      - name: Print nixpkgs version
-        run: nix-instantiate --eval -E '(import <nixpkgs> {}).lib.version'
       - name: Register Nix Channels
         run: |
           nix-channel --add https://releases.nixos.org/nixpkgs/nixpkgs-23.11pre509044.3acb5c4264c4/nixexprs.tar.xz nixpkgs
diff --git a/.github/workflows/ci-nix.yml b/.github/workflows/ci-nix.yml
index 6405f93d..270dafa8 100644
--- a/.github/workflows/ci-nix.yml
+++ b/.github/workflows/ci-nix.yml
@@ -5,11 +5,13 @@ on:
     paths:
       - '.github/workflows/ci-nix.yml'
       - '*.nix'
+      - 'flake.*'
       - 'Makefile.toml'
   pull_request:
     paths:
       - '.github/workflows/ci-nix.yml'
       - '*.nix'
+      - 'flake.*'
       - 'Makefile.toml'
   schedule:
     # Every 10:42 JST
@@ -25,5 +27,5 @@ jobs:
       - uses: actions/checkout@v3
       - uses: DeterminateSystems/nix-installer-action@v4
       - uses: DeterminateSystems/magic-nix-cache-action@v2
-      - run: nix-shell --run 'echo This step should be done before any other "nix-shell" steps because of measuring Nix build time'
-      - run: nix-shell --run 'makers ci-dev'
+      - run: nix develop --command echo 'This step should be done before any other "nix develop" steps because of measuring Nix build time'
+      - run: nix develop --command makers ci-dev
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 3a03a783..b5b2fa31 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -1,7 +1,7 @@
 # Development
 
 1. Install [Nix](https://nixos.org/) package manager
-1. `nix-shell --command 'makers setup'`
+1. `nix develop --command makers setup`
    - `direnv allow` may not work if you have not completed all the installation steps
 
 ## Note
diff --git a/README.md b/README.md
index 46ced2de..d74d9b0f 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,7 @@ Also known as [盆栽(bonsai)](https://en.wikipedia.org/wiki/Bonsai) 🌳
 
 1. Install [Nix](https://nixos.org/) package manager
 1. Install [home-manager](https://github.com/nix-community/home-manager)
-1. `nix-shell --command 'makers apply'`
+1. `nix develop --command makers apply`
 
 ## I don't know ??? - I have just installed OS, I am 🚼
 
diff --git a/default.nix b/default.nix
deleted file mode 100644
index f189eb29..00000000
--- a/default.nix
+++ /dev/null
@@ -1,27 +0,0 @@
-{ pkgs ? import
-    (fetchTarball
-      "https://releases.nixos.org/nixpkgs/nixpkgs-23.11pre509044.3acb5c4264c4/nixexprs.tar.xz")
-    { }
-}:
-
-pkgs.mkShell {
-  buildInputs = with pkgs;
-    [
-      # https://github.com/NixOS/nix/issues/730#issuecomment-162323824
-      bashInteractive
-
-      dprint
-      shellcheck
-      shfmt
-      nil
-      nixpkgs-fmt
-      gitleaks
-      cargo-make
-      typos
-      go_1_20
-
-      # To get sha256 around pkgs.fetchFromGitHub in CLI
-      nix-prefetch-git
-      jq
-    ];
-}
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 00000000..847f47f2
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,56 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1689068808,
+        "narHash": "sha256-6ixXo3wt24N/melDWjq70UuHQLxGV8jZvooRanIHXw0=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "919d646de7be200f3bf08cb76ae1f09402b6f9b4",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "narHash": "sha256-BXtO36CWk7WnRJVsKBV0uZQ9VWfduKbfrutkYUxQGmg=",
+        "type": "tarball",
+        "url": "https://releases.nixos.org/nixpkgs/nixpkgs-23.11pre509044.3acb5c4264c4/nixexprs.tar.xz"
+      },
+      "original": {
+        "type": "tarball",
+        "url": "https://releases.nixos.org/nixpkgs/nixpkgs-23.11pre509044.3acb5c4264c4/nixexprs.tar.xz"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 00000000..128fd240
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,43 @@
+{
+  inputs = {
+    # Candidate channels
+    #   - https://github.com/kachick/anylang-template/issues/17
+    #   - https://discourse.nixos.org/t/differences-between-nix-channels/13998
+    # How to update the revision
+    #   - `nix flake update --commit-lock-file` # https://nixos.org/manual/nix/stable/command-ref/new-cli/nix3-flake-update.html
+    # TODO: Refer a popular channel in another issues
+    # nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    nixpkgs.url = "https://releases.nixos.org/nixpkgs/nixpkgs-23.11pre509044.3acb5c4264c4/nixexprs.tar.xz";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+      in
+      {
+        devShells.default = with pkgs;
+          mkShell {
+            buildInputs = [
+              # https://github.com/NixOS/nix/issues/730#issuecomment-162323824
+              bashInteractive
+
+              dprint
+              shellcheck
+              shfmt
+              nil
+              nixpkgs-fmt
+              gitleaks
+              cargo-make
+              typos
+              go_1_20
+
+              # To get sha256 around pkgs.fetchFromGitHub in CLI
+              nix-prefetch-git
+              jq
+            ];
+          };
+      }
+    );
+}