diff --git a/dist/index.js b/dist/index.js
index f148638..84eb1ff 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -52058,7 +52058,8 @@ async function installBundler(bundlerVersionInput, lockFile, platform, rubyPrefi
     console.log(`Using Bundler 1 shipped with ${engine}`)
   } else {
     const gem = path.join(rubyPrefix, 'bin', 'gem')
-    await exec.exec(gem, ['install', 'bundler', '-v', `~> ${bundlerVersion}`, '--no-document'])
+    const bundlerVersionConstraint = bundlerVersion.match(/^\d+\.\d+\.\d+/) ? bundlerVersion : `~> ${bundlerVersion}`
+    await exec.exec(gem, ['install', 'bundler', '-v', bundlerVersionConstraint, '--no-document'])
   }
 
   return bundlerVersion
diff --git a/index.js b/index.js
index 7cfe526..ae962ae 100644
--- a/index.js
+++ b/index.js
@@ -229,7 +229,8 @@ async function installBundler(bundlerVersionInput, lockFile, platform, rubyPrefi
     console.log(`Using Bundler 1 shipped with ${engine}`)
   } else {
     const gem = path.join(rubyPrefix, 'bin', 'gem')
-    await exec.exec(gem, ['install', 'bundler', '-v', `~> ${bundlerVersion}`, '--no-document'])
+    const bundlerVersionConstraint = bundlerVersion.match(/^\d+\.\d+\.\d+/) ? bundlerVersion : `~> ${bundlerVersion}`
+    await exec.exec(gem, ['install', 'bundler', '-v', bundlerVersionConstraint, '--no-document'])
   }
 
   return bundlerVersion