Recently, the demand for excimer irradiation equipment is increasing with the diffusion of LCD TVs and other LCD devices. However, luminous energy of excimer lamps decreases over time. Conventionally, an illuminometer is placed near each lamp to detect and rectify the declining luminous energy. In the present study, the authors succeeded in development of a lighting device that controls this luminous-energy decline by a circuit configuration, which resulted in prolongation of the service life of excimer lamps.