To prevent the difficulty of visual confirmation of a gate related device due to the backlight condition and to simplify the exterior works by forming an illuminating device, a human body detecting sensor, an illuminance sensor, and a flickering and illuminance control circuit into a unit, and installing the unit on a gatepost.

An illuminating device A for a gate and its periphery formed as a unit by an illuminating device 2, a human body detecting sensor 3, an illuminance sensor and a lighting control circuit is installed on a gatepost 1. The illuminating device 2 is controlled to flicker by detecting the day or night by the illuminance sensor, and be reduced to the half in quantity of light according to a signal from the human body detecting sensor 3, and be automatically returned to the 100% lighting state after the lapse of fixed time. A person who approaches the gatepost 1 during lighting in the night can easily visually confirm the gate related devices 4 such as interphone 4a, a name plate 4b and the like without backlighting by 50% reduction in quantity of light. Furthermore, since the illuminance is automatically returned after the lapse of fixed time, no obstacle is caused in furylarproof view point. The construction can be simplified by disposing the gate related devices 4 to be concentrated so as to reduce the cost of exterior works.