To dispense with a centrifugal clutch and to reduce the length of a support portion of a movable pulley.

The transmission includes a drive pulley 60 supported by a primary shaft 51; a driven pulley 70 supported by a secondary shaft 52; a V-belt 53 laid between the drive pulley and the driven pulley; a drive-side actuator 90F which changes the groove width of the drive pulley 60 by sliding a movable pulley 62 in the drive pulley in the axial direction; and a driven-side actuator 90R which changes the groove width of the driven pulley 70 by sliding a movable pulley 72 in the driven pulley in the axial direction. When a vehicle is stopped, the groove widths of the drive pulley 60 and the driven pulley 70 are extended respectively by the drive-side actuator 90F and the driven-side actuator 90R so that no power is transmitted from the drive pulley to the driven pulley through the V-belt.