To provide a safe for crime prevention extremely safe for crime prevention since the safe itself cannot be carried away once installed.

This safe comprises an outer box 5 fixed to the prescribed member of an automobile and an inner box 10 installed in the outer box driveably so as to take a first position and a second position and having an openable door 13 installed in the opening thereof. When the inner box 10 takes the first position, a key hole 15 for operating the openable door 13 of the inner box 10 is concealed by the outer box 5, and when the inner box 10 takes the second position, the key hole 15 is exposed from the outer box 5 to the outside and the key operation is enabled. When the inner box 10 is manually driven to the first position, it is locked by a lock mechanism, and when air pressure acts on the inner box, the lock mechanism is released and the inner box is driven to the second position by the air pressure.