An open/close actuating mechanism control device for a vehicle includes: an actuating mechanism (24, 30) that is exposed to outside air and that opens or closes on the basis of whether a predetermined condition is satisfied; an open/close failure determining unit (32) that determines whether an open/close failure of the actuating mechanism (24, 30), in which the actuating mechanism (24, 30) fails to open or close, has occurred; an outside air temperature detecting unit (36, 32) that detects an outside air temperature; and a determination timing changing unit (32) that changes timing, at which the open/close failure determining unit (32) determines that the open/close failure of the actuating mechanism (24, 30) has occurred, on the basis of the outside air temperature detected by the outside air temperature detecting unit (36, 32).