PURPOSE: To eliminate the need for a supervisor to watch a monitor at all times and to prevent mis-supervision due to human factor by using a supervisory camera and a supervisory microphone and generating a fault detection signal only when a fault takes place in a supervisory area.

CONSTITUTION: An error threshold level discrimination means 19 receives an error result between a picture and a voice to discriminate the comparison with an error threshold level. That is, a picture error threshold level is compared with a picture error inputted from a picture comparison and error arithmetic operation means 9, and a voice error threshold level is compared with a voice error inputted from a voice comparison and error arithmetic operation means 16 and a fault detection signal is generated only when both the values exceed respectively both the threshold levels. Furthermore, the error threshold level discrimination means 19 uses a total control means 18 to revise the picture and voice threshold levels optionally similarly to the case of a picture signal processing section. Thus, the supervisory equipment with high reliability is obtained by comparing the changes in the picture and voice with the error threshold level respectively in this way.