An illuminance sensor setting device includes: an illuminance sensor that outputs a signal for switching a lighting apparatus, and a setting unit that performs setting of the illuminance sensor. The illuminance sensor and the setting unit are provided separately from each other, and are connected to signal lines. The setting unit has a configuration to set a sensor address of the sensor, a control address of the lighting apparatus, and an illuminance reference for switching the lighting apparatus. The setting unit transmits to the signal line the setting signal and the sensor address. Thus, even if the illuminance sensor is provided on, for example, the ceiling in the vicinity of the lighting apparatus, the setting unit can be provided at any place, such as a wall, where the setting unit can be easily operated, and work for settings is facilitated.