To eliminate wiring and connection works of wiring harnesses, and to improve assembly workability.

A transmitter 16 is connected to a power supply, and a waveguide 22 is composed of a closed space defined by a dash panel 18 and an instrument panel 20. The antenna 16A of the transmitter 16 is inserted into the waveguide 22 and microwaves emitted from the antenna 16A are transmitted through the waveguide 22. A diode receiver 30 is provided for an electronic apparatus 28 such as meters, audio equipment, an airbag apparatus, or the like and the antenna 30A of the diode receiver 30 is inserted into the waveguide 22. The antenna 30A receives the microwaves transmitted through the waveguide 22, so as to supply power to the electronic apparatus 28.