diff --git a/setup.ps1 b/setup.ps1
index 33ab217..ea3d0e1 100644
--- a/setup.ps1
+++ b/setup.ps1
@@ -53,7 +53,19 @@
 
 $slnPath = Join-Path $PSScriptRoot "TIASshot.sln"
 if (Test-Path $slnPath) {
-    nuget restore $slnPath
+    # nuget.exe が PATH になければリポジトリルートにダウンロードして使用する
+    $nugetCmd = Get-Command nuget.exe -ErrorAction SilentlyContinue
+    if ($nugetCmd) {
+        $nugetExe = "nuget.exe"
+    } else {
+        $nugetExe = Join-Path $PSScriptRoot "nuget.exe"
+        if (-not (Test-Path $nugetExe)) {
+            Write-Host "  nuget.exe をダウンロードします..." -ForegroundColor White
+            Invoke-WebRequest -Uri "https://dist.nuget.org/win-x86-commandline/latest/nuget.exe" `
+                -OutFile $nugetExe
+        }
+    }
+    & $nugetExe restore $slnPath
     Write-Host "  NuGet パッケージの復元が完了しました．" -ForegroundColor Green
 } else {
     Write-Host "  TIASshot.sln が見つかりません．手動で復元してください．" -ForegroundColor Red