A universal joint includes a driving portion and a joint head. The driving portion includes a ball nest and a polygonal column disposed within the ball nest. The joint head includes a working end portion and a ball head portion, and the ball head portion is rotatably and swingably disposed within the ball nest. A shaped of the ball head portion corresponds to a shaped of the ball nest, and the polygonal column is co-rotatable with the ball head portion. The ball head portion including a polygonal groove, and the polygonal column is inserted within the polygonal groove.