To provide a car protective cover which is lightweight and easy to handle by employing the cover of a double sheet structure and filling air in an airtight double wall, capable of sufficiently protecting a car body even against a considerably large external force, and flattened by discharging internal air and easily accommodated in a rear trunk of the car when the cover is not in use.

A cover 2 to cover an outer surface of a car 1 when the car is parked is formed of a double sheet structure comprising an airtight inner sheet 2a and an airtight outer sheet 2b with edge parts thereof adhered to each other, an intake/exhaust valve 3 for feeding air in an airtight space inside the double sheet structure and discharging air from the airtight space is provided, and the inner sheet 2a is formed of a sheet material thinner than that of the outer sheet 2b.