1. A positioning information forming apparatus that forms positioning information used for detection of an object on the basis of an image based on information detected by a radar, and on an image taken by a stereo camera, comprising; a first coordinate transforming section that transforms a coordinate system of radar distance map information associating a coordinate group of the image based on the information with distance information, into a reference coordinate system defined by a parallax-axis and one of the coordinate axes of an image plane coordinate system at a virtual position of installation of the positioning information forming apparatus; a first smoothing section that smooths the transformed radar distance map information by applying a first smoothing filter only in the one of the coordinate axes direction; a second coordinate transforming section that transforms a coordinate system of camera distance map information associating a coordinate group of the taken image with distance information, into a reference coordinate system; a second smoothing section that smooths the transformed camera distance map information by applying a second smoothing filter only in the parallax-axis direction; and a combination section that forms combined map information by combining the smoothed radar distance map information and the smoothed camera distance map information.