To easily set sensitivity or target illuminance without wiring, and shortening the battery life of a wireless remote controller.

In the treatment part 112 of a illuminance sensor part 11, detected illuminance in an illuminance detection part 111, and set target illuminance are compared to determine a dimming level for conforming both the sides, and the dimming level is transmitted to the signal transmitting/ receiving part 131 of a luminaire 13 from a wireless signal transmitting/receiving part 113. A treatment part 132 imparts a received dimming level to a dimming control circuit 133, to dim and control an illumination lead 134. The treatment part 122 of a remote control 12 transmits sensitivity and target illuminance, inputted from an input part 124, to the signal transmitting/receiving part 113 from a signal transmitting/receiving part 121. The treatment part 112 sets sensitivity and target illuminance, received in the signal transmitting/receiving part 113. This constitution eliminates a wiring between the sensor part 11 and the luminaire 13, also an illuminance detection element constantly consuming power by the remote control 12.