To discriminate an abnormality from only an image picked up by a camera picking up a monitor area.

The system is provided with an image compression section 21 that compresses image data obtained from an image pickup section 1 such as a camera installed in a monitor area, a processing section 23 sets a threshold level to discriminate occurrence of a fault based on a data amount of the compressed image data obtained by the image compression section 21 and when there is a fluctuation in the amount of the compressed image data in excess of a prescribed range by using an abnormality didcrimination algorithm, it is discriminated that there is a change in the image of the monitor area picked up by the image pickup section 1 and an abnormality detection signal is outputted.