PURPOSE: To unlock a lid without operating a VTR with the lid locked, prevent the VTR from malfunctioning, and improve the operativity by providing a lever which presses an unlocking part associatively with a cassette when the cassette is inserted securely.

CONSTITUTION: When the cassette 1 is inserted to a prescribed position, the front surface of the cassette 1 abuts on a projection piece 16, a projection piece 17 presses and turns on a detection switch 18, and the 1st arm 9 rotates around a rotating shaft 8 into a cassette receiving metallic fixture 5 to press the unlocking part 3. Consequently, the cover 2 is unlocked. Thus, the malfunction of the VTR is prevented and the operativity is improved.