The mobile unit position detecting apparatus generates target data by extracting a target from an image shot by the image capturing device, extracts target setting data that best matches the target data, is prerecorded in a recording unit and is shot for each target, obtains a target ID corresponding to the extracted target setting data from the recording unit, detects position data associated with the obtained target ID, tracks the target in the image shot by the image capturing device, and calculates an aspect ratio of the target being tracked in the image. If the aspect ratio is equal to or lower than a threshold value, the mobile unit position detecting apparatus outputs the detected position data.