In order to investigate influence of moon light to the fishing of Pacific saury stick-held dip net fishery in the northwestern Pacific Ocean, casting number, catch and CPUE were analyzed between the full moon and the new moon phases. Based on analyses of data taken from 8 vessels during 1992~2002, casting numbers at the full moon phase and the new moon phase were 110.3 and 121.0 times, respectively, and the first was lower than the latter by 8.8%. Catches of the full moon phase were higher than the new moon phase by 12.5% and CPUE expressed in ton/day and ton/haul were also higher by 31.5%, 26.1% respectively.