Bacterial eliminator

The object of the present invention is to provide a bacterial eliminator suitable for reduction in size or lowering of cost. A UV filament lamp is preheated by a control section even when water is not flowing. Consequently, the UV filament lamp can be lit immediately upon flow of water. The lamp can thereby be kept unlit when water is not flowing. Consequently, the lamp is unlikely to overheat easily when water is not flowing. Also, power consumption is reduced and lifespan of the lamp can be prolonged. If the lamp overheats and unheated water flows in, there is a possibility of the lamp being damaged. In order to avoid such damage, a special structure or material is normally required. Since overheating of the lamp can be avoided with the invention, a special structure or material for avoiding damage to the lamp due to unheated water are not necessary, or the structure can be simplified.