A planetary gear type transmission includes a planetary gear mechanism including a sun gear, a ring gear, and a planetary carrier which all have the same axis, an output shaft having the same axis as the planetary gear mechanism, a sleeve supported movable in an axial direction by the output shaft, an inner piece connected to the sleeve while the sleeve is approaching the planetary gear mechanism and including a first inner spline, and an outer piece connected to the sleeve while the sleeve is separating from the planetary gear mechanism and including a second outer spline. The sleeve includes a first outer spline fitted to the first inner spline and a second inner spline fitted to the second outer spline. A distance between the second inner spline and the planetary gear mechanism is smaller than a distance between the first outer spline and the planetary gear mechanism.
