To provide mobile object and vehicle position detectors capable of confirming the vehicle position when it is moving and stopping or parking.

A vehicle 11 is mounted with a portable telephone 20 communicating with a base station 12 having relatively limited base station areas 15. The portable telephone 20 communicates with a nearest base station 12 by receiving working power supply from the vehicle 11 and notifies information of the base station 12 to a center 14 through a communication exchange 13. Under a state where the engine of the vehicle 11 went out, working power is supplied intermittently from a timer circuit 22 to a portable telephone 21 thus preventing overdischarge of a battery 31.