An imaging apparatus includes: an image creating section imaging a predetermined surveillance range and creating image data; an image processing section in which computing processing means having a predetermined processing ability performs first image processing of detecting an abnormality in the surveillance range in accordance with the image data and generating a first detection signal and second image processing of converting the image data to a predetermined data format in parallel; and a determination processing section determining whether a predetermined subject under surveillance exists in the surveillance range or not based on the first detection signal, generating and supplying a first control signal to the image processing section if it is determined that the subject under surveillance does not exist, and generating and supplying a second control signal to the image processing section if it is determined that the subject under surveillance exists.