To provide a lighting system that easily implements a lower manufacturing cost and a smaller size while using contactless power transmission.

In the lighting system that supplies power from a power transmission section to drive a passive lighting device and changes lighting luminance of the passive lighting device, the power transmission section has a power control circuit connected to an external power supply, at least one power transmitting coil for converting high frequency output power sent from the power control circuit to electromagnetic power to be wirelessly transmitted to the passive lighting device, and a traveling wave detection circuit for detecting a traveling wave propagated from the power control circuit to the power transmitting coil, the passive lighting device has at least one power receiving coil for receiving and converting to driving power the electromagnetic power wirelessly transmitted from the power transmitting coil, and a light emission device for emitting light in response to the driving power supplied via the power receiving coil, and the power control circuit controls a power value of the high frequency output power on the basis of a power value of the traveling wave.