A motorcycle, comprising: a frame extending in a longitudinal direction of the vehicle; a driving unit pivotably supported by the frame, the driving unit comprising an engine and a power transmission case accommodating a belt continuously variable transmission configured to transmit a driving force from the engine to a rear wheel; a seat disposed above the engine, the seat configured to be opened/closed; a storage box disposed under the seat; a lock mechanism (41, 56) disposed behind the storage box, the lock mechanism (41, 56) configured to lock the seat to the frame; a pair of right and left side covers for covering at least right and left lateral sides of the storage box; a tail light unit (40, 57) disposed behind the lock mechanism (41, 56), at least a part of the tail light unit (40, 57) disposed between the side covers, and a cooling duct (50, 64, 70) having a first end and a second end, the first end of the cooling duct (50, 64, 70) connected to the power transmission case, the second end of the cooling duct (50, 64, 70) having an opening (52b, 67a), the opening (52b, 67a) positioned between the lock mechanism (41, 56) and the tail light unit (40, 57), the opening (52b, 67a) positioned within a space surrounded by the storage box, the side covers and the tail light unit (40, 57), wherein the storage box and the tail light unit are longitudinally disposed one behind the other, and wherein the space is ensured between the storage box and the tail light unit for disposing the lock mechanism and a wiring of a light bulb of the tail light unit and for allowing the exchange of the light bulb of the tail light unit to be carried out. a frame extending in a longitudinal direction of the vehicle; a driving unit pivotably supported by the frame, the driving unit comprising an engine and a power transmission case accommodating a belt continuously variable transmission configured to transmit a driving force from the engine to a rear wheel; a seat disposed above the engine, the seat configured to be opened/closed; a storage box disposed under the seat; a lock mechanism (41, 56) disposed behind the storage box, the lock mechanism (41, 56) configured to lock the seat to the frame; a pair of right and left side covers for covering at least right and left lateral sides of the storage box; a tail light unit (40, 57) disposed behind the lock mechanism (41, 56), at least a part of the tail light unit (40, 57) disposed between the side covers, and a cooling duct (50, 64, 70) having a first end and a second end, the first end of the cooling duct (50, 64, 70) connected to the power transmission case, the second end of the cooling duct (50, 64, 70) having an opening (52b, 67a), the opening (52b, 67a) positioned between the lock mechanism (41, 56) and the tail light unit (40, 57), the opening (52b, 67a) positioned within a space surrounded by the storage box, the side covers and the tail light unit (40, 57), wherein the storage box and the tail light unit are longitudinally disposed one behind the other, and wherein the space is ensured between the storage box and the tail light unit for disposing the lock mechanism and a wiring of a light bulb of the tail light unit and for allowing the exchange of the light bulb of the tail light unit to be carried out.