To reduce radiation noises which occur when a plurality of lamps are controlled simultaneously.
When controlling four stop lamps included in lamp devices mounted on the right and left of a vehicle, a stop-lamp controlling requirement is judged (a2) in a (t)-time period. If the requirement is that the lamps be turned on, from the lamp 1 to the lamp 4 are turned on one by one at every period (a3-a10). If the stop lamp controlling requirement is that the lamps be turned off, from the lamp 1 to the lamp 4 are turned off in sequence (a11-a18). By setting the time (t) to be sufficiently longer than the time during which rush currents flow in the lamps from 1 to 4 but sufficiently short as viewed by the human eye, the lamps are allowed to appear to be simultaneously turned on or off to the unaided eye, and noises can be reduced.
UEHARA SHIGERU
HIGUCHI YOICHIRO
