Ultraviolet (UV) laser lights were irradiated on Si field emitter arrays before and during electron emission to investigate the surface cleaning effect of laser light irradiation. UV light irradiation for 2-10 min before electron emission in a vacuum resulted in enhanced electron emission by 50%, which gradually decreased after further aging. Laser light irradiation during electron emission could induce enhanced electron emission by a factor of 2.4 due to photoinduced carrier generation and surface cleaning, and higher electron emission by a factor of 2 than the initial emission was observed even after laser light irradiation and prolonged aging for 20 h.