Abstract: The power transmission apparatus for a vehicle has a main shaft having drive gears mounted thereto and a countershaft having driven gears mounted thereto, and the respective shafts are attached to a case. A reverse shaft attached to the case has an idler gear for reverse operation or a reverse idler gear rotatably attached thereto which is engaged with a drive gear for reverse operation and a driven gear for reverse operation. The reverse shaft has a projection which is integrally formed thereon and is in contact with one side surface of the reverse idler gear, and has a washer mounted thereto which is in contact with the other side surface of the reverse idler gear.