A car finder system has a portable terminal that receives a preset operation performed thereon for wirelessly transmitting a preset car finder instruction. A communication device of the car finder system receives the preset car finder instruction from the portable device, and repeatedly transmits a preset car finder signal to an in-vehicle device, which is disposed in a vehicle. The in-vehicle device performs an external notification operation when it receives the preset car finder signal. The communication device ends the transmission of the preset car finder signal when a predetermined condition is met.