A multistage transmission includes a swing claw member having a pin-receiving portion adapted to receive a pin member and an engaging claw portion on respective sides opposite to each other with respect to swing center, and swung by the advancement and retraction of the pin member to allow the engaging claw portion to establish engagement and release the engagement; and biasing means for biasing the swing claw member in a swing direction of bringing the engaging claw portion into engagement. The biasing means is a compression spring interposed between the inner surface of the engaging claw portion of the swing claw member and the opposing surface of the gear shaft. The multistage transmission uses multiple swing claw members of the same kind, instead of swing claw members of different kinds.