The present invention teaches a remote starting control system having a simple construction and being low in cost, that can be mounted on a vehicle having an immobilizing function. The system, which is mounted on a vehicle equipped with an immobilizer for capturing a code output in response to an insertion of an ignition key into a key cylinder and permitting an engine start when judging the captured code to be a unique code of the vehicle so as to control engine starting according to an instruction from a portable transmitter, comprises a device for storing a code in an EEPROM each time the code is supplied to a signal line, and a device for supplying the code stored in the EEPROM to the immobilizer when receiving a start instruction of the engine from the portable transmitter.