To provide a simple retreat parking support device at a low price.

This retreat parking support device is constituted by an irradiation device carried on a vehicle and having an optical source for generating a predetermined figure on a predetermined position of the vehicle rear part when irradiating a flat road surface, a photographing device capable of photographing the road surface including the figure generated by the irradiation device, and an image processing device detecting existence or no-existence of a car stop based on the difference between the figure generated on the road surface by the irradiation device and photographed by the photographing device and the predetermined figure. Thus, the simple retreat parking support device can be achieved at the low cost.