To provide a ventilator for a vehicle having a structure where an opening valve easily rotates with respect to the device body and its molding die.

The ventilator for the vehicle comprises the resin-made device body 2 having a ventilation hole 4 and a slit 5 formed over it. The ventilator comprises an open valve 3 that has a locking section 5 formed wider than the width of the slit, a flat plate section 8, and a connecting section 7 for connecting the locking section to the flat plate section. The connecting section is inserted into the slit and locked to the slit by the locking section, the lower end of the flat plate section is set free, and the ventilation hole is blocked by the flat plate section. The open valve 3 is made of elastic material. The open valve is opened by air pressure in the car to exhaust the air in the car to the outside. The locking section rotatably contacts with the slit, and the atmospheric pressure applied to the flat plate rotates the locking section to open the flat plate.