Provided is a shaft-and-yoke coupling structure for coupling a steering transmission shaft and a yoke of a universal joint. An end portion of the steering transmission shaft joined to the yoke has a stepped portion and an insertion convex portion protruding from the stepped portion in the axial direction of the steering transmission shaft. The yoke has an annular receiving portion facing and fixed to the stepped portion via a welded portion and an insertion recess portion surrounded by the receiving portion in which the insertion convex portion is inserted. The insertion convex portion and the insertion recess portion are arranged to be engaged with each other with a predetermined amount of play in the direction of rotation when the welded portion is broken.