To provide a transmission capable of restraining generation of loss torque, without allowing mutual contact between tapered surfaces of relatively rotating members, when a synchronizer ring is freely rotating.

This transmission 10 includes a rotary shaft 2, a clutch hub 3, a shift gear 5, a gear piece 6, the synchronizer ring 7, a sleeve, and a pressing member 81 for pressing the synchronizer ring 7 to the clutch hub 3 side by converting centrifugal force by rotation of the rotary shaft 2 in the direction for expanding between the gear piece 6 and the synchronizer ring 7, between the gear piece 6 and the synchronizer ring 7.