The exchange time information to be acquired from an LED illumination lamp by an illumination instrument or the exchange time information to be stored by the illumination instrument itself is recognized by a controller via an ON/OFF control-dedicated switch control line or a general-purpose power line. The exchange time information is acquired in an OFF period of the LED illumination lamp ON-period noise. The exchange time information acquisition function is checked on a daily basis so as to cope with an alarm after a long period. The exchange time check result is stored so as to execute the alarm at an appropriate timing. The exchange time information held by the LED illumination lamp itself is transmitted firstly to the illumination instrument by simple information transmission means. The information is recognized by using a control path existing between the illumination instrument and the controller at hand.