A pre-determination process is executed for setting a person determination detection frame in a moving body detection frame surrounding a moving body region detected from an image and determining whether the image in the person determination detection frame is a person and a final determination process of analyzing a distribution state in a moving body detection frame determined to include a person in the pre-determination process and finally determining whether the image in the person determination detection frame is a person based on an analysis result. In the final determination process, an occupancy rate in a specific region in the moving body detection frame determined to include a person in the pre-determination process is calculated, and the image in the person determination detection frame is determined to be a person based on the occupancy rate.