To provide a transmission capable of improving riding quality of a vehicle and the like by improving buffer function of a spike torque while reducing costs and size.

An input shaft 3 connected to a start clutch 2 includes a first input shaft 3a and a second input shaft 3b. Drive gears Dv are fixed to a first main shaft 4 and a second main shaft 5, and driven gears Dn are relatively rotatably disposed on an output shaft 6. The driven gears are respectively connected or disconnected to the output shaft by gear switching mechanisms 100a, 100b. The first main shaft, the second main shaft, the second input shaft are provided with a shaft switching mechanism 50 for switching a power transmission path to the first main shaft or the second main shaft. A buffer mechanism 300 is disposed between the first input shaft and the second input shaft to cut spike torque generating in switching the power transmission path to a predetermined torque.