1. An in-vehicle image processing device for recognizing a parkable area around a vehicle, the device comprising: an overhead image generation section configured to generate an overhead image with a road surface as a reference by converting a view point of an image of a nearby vehicle and the road surface taken by a vehicle-mounted camera; a tire recognition section configured to recognize tires of the nearby vehicle from the image or the overhead image; a three-dimensional object recognition section configured to recognize, from the camera image or the overhead image, three-dimensional objects including a vehicle body of the nearby vehicle; an area-under-vehicle recognition section configured to calculate a ground contact position of the tire and an above-ground height from the ground contact position to the vehicle body and recognize an area under the vehicle body on the road surface from the overhead image based on the above-ground height; and a parkable area recognition section configured to recognize an area occupied by the vehicle body and the area under the vehicle body as a non-parkable area and recognize, based on the non-parkable area, a parkable area on the road surface.