An image acquisition part acquires a plurality of shot images captured by a plurality of cameras disposed on a vehicle, each of the plurality of shot images showing a periphery of the vehicle. An image composer projects data of the plurality of shot images onto a virtual projection surface corresponding to the periphery of the vehicle, and generates a composite image showing the periphery of the vehicle viewed from a virtual viewpoint, using the data projected onto the virtual projection surface. The image composer uses, as the virtual projection surface, a special virtual projection surface that includes a curved area having an upward convex curve. The curved area includes an area where a distance from a location of the vehicle is relatively short and a slope is relatively high, and another area where the distance from the location of the vehicle is relatively long and the slope is relatively low.