PURPOSE: To obtain a magnetic recording and reproducing device which is switched from intermittent recording to continuous recording by comparing preliminarily stored sound information with sound information inputted from the external and discriminating the emergency state in the case of disaccord.

CONSTITUTION: External sounds from an external input terminal 2 and sound information preliminarily stored in a sound storage part 3 are compared with each other by a comparator 4, and a control part 5 receives the output signal of the sound comparator 4 to control the recording state.