To investigate a proper sampling method for larval fish in the western coastal waters, the abundances of larval fish sampled at upper and lower layers during the day and nighttime were compared. The difference in the abundances at upper and lower layers seems to be related to the diurnal vertical migration of larval fish. Therefore, samples at upper layer during the day causes an underestimation of the number of species and the abundance. As the abundances through whole water column during the day is not significantly smaller than during the nighttime. samples obtained by oblique tow through whole water column during the day can be used to estimate the abundance of fish larvae.