PURPOSE: To inhibit an operation due to the third person or the like not only to a keyboard but also to an external storage equipment or the like by providing an external storage equipment lock mechanism as a constitutive element so as to lock the operation to the external storage equipment while being interlocked with the lock operation of a keyboard lock mechanism.

CONSTITUTION: When a key 5 is inserted to a key switch 3 and turned, a pawl 4 for lock is inserted to the back of a push button 2, and the forward and backward movement of the push button 5 is restricted. Therefore, a floppy disk ejecting mechanism 6 can not be operated by pushing the push button 2, and an FDD 1 is turned to a lock state. Simultaneously, a keyboard lock signal is generated from a switch part 7 and the keyboard is turned to the lock state as well. In this way, the operation not only to the keyboard but also to the external storage equipment such as the FDD or the like is locked while being interlocked with the lock operation of the keyboard lock mechanism. Thus, the system can be sufficiently protected from unexpected contact or the like due to the third person.