PURPOSE: To perform high-speed dubbing without fail even when an operation ineffective key is operated by mistake, by driving an operation ineffective switch associatively with a high-speed command key of a control system.

CONSTITUTION: When high-speed dubbing is carried out, a high-speed command is sent to a control circuit 40 with the high-speed command key 36b, and the control circuit 40 after turning on all operation ineffective switches 44A, 44B, 46A, and 46B by the high-speed command regardless of the state of operation keys 36k and 36l to make the operations of operating circuits 32A and 34B ineffective operates driving devices 20A and 20B, a sound recording amplifier 22A, and a reproduct amplifier 24B to perform the dubbing while driving cassette tapes 10A and 10B at a high speed. Consequently, reproduce signal 100B of the reproduce amplifier 24B which is increased to a high frequency passes through the operating circuits 34B and 32A as it is and is supplied to the sound recording amplifier 22A to be recorded on the cassette tape 10A without any alteration.