PURPOSE: To perform three kinds of sound monitoring at the time of reproducing by superimposing a first audio signal to a second audio signal in which frequency is converted to the out of audio frequency band.

CONSTITUTION: The output of an audio signal input circuit 2 is converted in frequency by a frequency converter 3, the output of an audio signal input circuit 1 is mixed, processed by a signal processing block 4, recorded in a tape 7 through a recording and reproducing amplifier 5 and a magnetic head 6. In the converter 3, frequency of a first audio signal 1a is not converted, frequency of a second audio signal 2a is converted to a frequency band of the out of audio frequency band. At the time of reproducing, frequency of the second audio signal is converted to an audio frequency band without converting frequency of the first audio signal. Consequently, any of three kinds of audio output (the fist, the second or the mix) can be selected.