To improve the operability of an electric code lock by collating a password code with an input code, to store the specific value when matching is secured between the both codes and supplying or cutting the supply of power to a device after confirming the specific value, when the code lock is mounted on the device main body.

A proper password code is set in advance to an electric code lock of every cassette radio, set as a registration code and stored in an external memory. When the radio set is energized, the electric code lock confirms the specific value stored in the external memory, to store the prescribed value other than the specific value and also to supply power to a device. If no specific value is confirmed, the supply of power to the device in steps ST9 to ST13 is cut. In such a constitution, the electric code lock is immediately available at its next mounting time, as long as the password code is inputted when the code lock is dismounted from the device. Thus, the operability of the electric code lock is improved.