A ranging and communication multifunction system including a transmission unit and a receiving unit, and integrates two functions of ranging and communication in which the transmission unit includes a transmission circuit, a carrier wave modification device, and a transmission antenna. The receiving unit includes a receiving circuit, a wave detector, a low noise amplifier, and a receiving antenna, and a data modulation performed in the transmission circuit uses a PPM system. Thus, the receiving circuit provides a ranging circuit and a communication separately, so that the demodulation processing of ranging and communication can be performed in parallel.