PURPOSE: To keep a stair lamp lighted while a person is on the stairs by detecting a person using a human body detecting unit which monitors the stairs as a human body detection area, and then lighting a predetermined stair lamp with high luminance through a drive unit via a control unit.

CONSTITUTION: When a person goes up the stairs from first story 11 to second story 12 and enters a human body detection area A, the human body detecting unit 20A of a control box T1 is actuated and, because the stairway space is lighted with low illuminance, a control unit 30A generates a high luminance lighting command signal and transmits the signal to the photocoupler of a drive circuit unit 40A and at the same time the unit 30A starts measuring time. A stair lamp 16 is thereby lighted with high luminance via a TRIAC. The unit 30A continues transmitting high luminance lighting signals for a fixed time T0. When the unit 30A inputs a human body detection signal within the fixed time T0, high luminance lighting signals are generated for a fixed time T0 from this point of time. When the person goes through a landing 14C, then the person enters a detection area B and a human body detecting unit 20B is actuated and the unit 30A transmits a high-luminance lighting signal.