A robot wrist structure includes a first wrist arm rotatable about a first axis, a second wrist arm provided in a tip end portion of the first wrist arm and configured to swing about a second axis substantially intersecting the first axis, a wrist flange provided in a tip end portion of the second wrist arm and configured to rotate about a third axis in a skew position with respect to the second axis, an intermediate member fixed to the wrist flange, and a cable bundle connected to an end effector fixed to the intermediate member. The cable bundle extends through the second wrist arm, the wrist flange and the intermediate member and drawn out from the intermediate member to reach the end effector.