To exactly detect an intruding object by eliminating the influence of halation without using special hardware for adjusting quantity of incident light.

An intruding object detector extracts candidate regions of the intruding object from one frame portion of a picture (S1), determines whether or not each of intruding object candidates contains halation to classify each of the intruding object candidates into 'a halation candidate list LH' and 'an intruding object list L1' (S2). When one or more halation candidate regions are present, changing the indication value of an electronic shutter to the value which is made higher in speed by a certain amount than the present value (S3, S5); performing intrusion detection processing by limiting the processing target region in the picture for the next one-frame portion picture to the interior of the halation candidate regions (S6) to exactly detect the intruding objects by eliminating the influence of the halation.