A hydraulic excavator periodically measures its current location at predetermined time intervals by the GPS device in an inoperative state where its engine key is in the off position and sends the current location data and time data to a management server by a main controller and communicator. The management server receives the periodically sent location data at its communicator and successively stores it in its memory. The current location data and the measurement time data to provide a location confirmation service by a location information provider. Changes in location can be confirmed on a map, the movement of the hydraulic excavator can be tracked, and assistance can be given for confirmation of location and prevention of theft.