To provide a remote control system where a conventional portable telephone set or a simple portable telephone set is used without being modified and a controlled unit is remotely controlled.

A telephone set 12 or a portable telephone set 16 transmitting remote control information by a DTMF signal, a reception portable telephone set 3 receiving the DTMF signal, a microphone 4 converting the DTMF signal, which is sound-outputted from the reception portable telephone set 3, into an electric signal, a DTMF signal conversion means 5 converting the DTMF signal into a digital control signal and a decoding means 8 decoding the digital control data into the control signal of a controlled unit l are installed. An existing portable telephone set and a simple portable telephone set are used as the reception portable telephone set 3, and remote control information can be sent to the controlled unit from the telephone set and the portable telephone set in a remote place.