To provide a position management system capable of grasping the existing position of a vehicle parked on an optionally selected parking position without arranging a vehicle detection means in every parking position.

Each of vehicle number detectors 3A to 3L extracts vehicle number information from an image of the number plate of each vehicle and supplies the vehicle number information and the device number for identifying the vehicle number detector itself to a vehicle management device 1 through a communication equipment 2. The device 1 acquires the vehicle number information and the device number, retrieves and updates data on an entering vehicle. A block in which each vehicle is parked is identified based on device data expressing corresponding relation among the entering vehicle data, each vehicle number detector and each block of a parking lot. A display part 14 in the device 1 displays information indicating the identified result.