To provide a car carrier ship capable of excellently reducing wind pressure resistance without decreasing the number of loaded cars.

The car carrier ship 1 having a loading deck 2 for a plurality of cars has a stem side ship mooring deck 3 and a stern side ship mooring deck 4 in which a ship mooring machine is respectively arranged. Each stem side ship mooring window 6 provided to an outer board 5 surrounding the stem side ship mooring deck 3 can be closed with a cover 10. The car carrier 1 has a retractable flap F which can be developed to project outward from the outer board 5, promoting the inflow of air into the stern side ship mooring deck 4 via a stern side ship mooring window 7. Thereby, air can be fed into a negative pressure region to be formed near the stern side to restore pressure, decreasing the wind pressure resistance to the whole ship during the navigation of the car carrier ship 1.