To provide a small universal joint with excellent rust prevention, capable of correctly operating over a long period.

A pair of hubs is disposed at the ends of a driving shaft and a driven shaft, and has a pair of yokes fixedly disposed to the hubs and having pin holes disposed at the tip portions of the yokes and at relative positions with each other in a diameter direction. Block members have pin holes in four directions mutually perpendicular, and engages to the pair of yokes through pins knocked into the pin holes. The pair of hubs and the block members are made of an aluminum alloy and subjected to almite treatment to the surfaces thereof. The pin 4 is made of austenitic stainless steel. A ball bearing inserted in a gap between the pin and the pinhole is made of martensitic stainless steel.