A transmission includes a first shaft unit connected to a drive shaft of a drive unit. The first shaft unit includes a first shaft having a first shaft raceway surface on an outer peripheral surface thereof, a first output gear provided on the first shaft, a first outer ring attached to a first support part, the first outer ring having a first outer ring raceway surface on an inner peripheral surface thereof, and a plurality of first rolling elements disposed between the first shaft raceway surface and the first outer ring raceway surface.

A spherical roller bearing includes an inner ring, an outer ring, spherical rollers and a cage. The cage has an axially inner ring and an axially outer ring connected by a plurality of cage bars to form pockets to hold the rollers. Each cage bar has an axially extending curvature in the circumferential direction that is at least partially concave, and an axial distance between an apex of the curvature and an axial inner pocket side face is not equal to and preferably larger than a distance between the apex of the curvature and an axial outer pocket side face.