An antitheft system provided with: a control system arranged on a self-propelling movable object with an engine mounted thereon as a drive source and having a position detecting means for detecting a position of said movable object, a transmission/reception means for performing a transmission/reception to/from an outside and a processing means (2, 2a) for performing predetermined processing operations including outputs of run commands to said position detecting means and said transmission/reception means, and a control server arranged at a place different from said movable object for controlling information on said movable object, said information comprising position information detected by said position detecting means and transmitted via said transmission/reception means, a clocking means, wherein said processing means (2, 2a) receives signals from said clocking means, and a first power feeding means for controllably feeding or not feeding power to at least said position detecting means, characterized in that said antitheft system further comprises: a second power feeding means for controllably feeding or not feeding power to at least said clocking means; wherein said processing means allows said first power feeding means to continuously feed power until a first predetermined time elapses from a time point at which a stop signal for said engine is inputted, and after an elapse of said first predetermined time, repeatedly outputs an instruction signal, which permits feeding of power, at predetermined time intervals by said first power feeding means. a control system arranged on a self-propelling movable object with an engine mounted thereon as a drive source and having a position detecting means for detecting a position of said movable object, a transmission/reception means for performing a transmission/reception to/from an outside and a processing means (2, 2a) for performing predetermined processing operations including outputs of run commands to said position detecting means and said transmission/reception means, and a control server arranged at a place different from said movable object for controlling information on said movable object, said information comprising position information detected by said position detecting means and transmitted via said transmission/reception means, a clocking means, wherein said processing means (2, 2a) receives signals from said clocking means, and a first power feeding means for controllably feeding or not feeding power to at least said position detecting means, characterized in that said antitheft system further comprises: a second power feeding means for controllably feeding or not feeding power to at least said clocking means; wherein said processing means allows said first power feeding means to continuously feed power until a first predetermined time elapses from a time point at which a stop signal for said engine is inputted, and after an elapse of said first predetermined time, repeatedly outputs an instruction signal, which permits feeding of power, at predetermined time intervals by said first power feeding means. a second power feeding means for controllably feeding or not feeding power to at least said clocking means; wherein said processing means allows said first power feeding means to continuously feed power until a first predetermined time elapses from a time point at which a stop signal for said engine is inputted, and after an elapse of said first predetermined time, repeatedly outputs an instruction signal, which permits feeding of power, at predetermined time intervals by said first power feeding means.