To enable a vehicle position detecting device to detect the position of its own vehicle about a lane section marker at a high S/N ratio by detecting the position of the vehicle with respect to the lane section marker from the detection result of a marker detection means.

A transmitting means sends a radio wave toward the road surface around the vehicle and a receiving means receives its reflected wave separately as a vertical and a horizontal polarized wave. A marker reflected wave extracting means extracts the reflected wave from the lane section marker laid on the road surface according to the result of a comparison between the vertical and horizontal polarized components of the reflected wave and a marker detecting means detects the lane section marker according to the extracted reflected wave from the lane section marker. Then the position of the vehicle about the lane section marker is detected from the detection result. Of this device, a signal processing circuit 31 detects the position of the lane section marker according to beat signal data from a subtracting process circuit 30 and also detects the position of a body other than the lane section marker according to beat signal data from an FFT processing circuit 28.