PURPOSE: To enable monitoring the recording state of a magnetic tape by checking the recording state automatically every time a recording mode is released and by issuing alarms in case of determination in the recording state.

CONSTITUTION: Upon receiving stop instructions by recording recording signal on a magnetic tape 20 through a heat block 18, a system controller 12 keeps on recording for a giving time and then sets operation at the reproduction mode to reproduce recording while winding up the tape 20 by a prescribed quantity. Its reproduced signal is input into a recording reproduced signal processor 3 and an envelope detector 10. In case of improper recording due to jamming of the head A, reproduced signal level (b) decreases to make envelop detection level (c) come below a prescribed level with the result that reproduced level detection output (e) shows a low level. In case of low output (e), a reproduced level judge means 13 judges the reproduced level to be below a prescribed value and sends light-up command to an alarm means 14 to light up a display 7.