The relationship between the number of age 0 fish and the biomass of age 1 fish in the previous year and the relationship between the number of age 1 fish and the number of age 0 fish in the previous year are observed for Pacific saury to understand the early and late life stage survival processes, taking into account the effect of environmental change. The number of age 0 fish were well explained by the Beverton-Holt model with environment indices, indicating that Pacific saury recruitment is determined both by the amount of spawner and environment. The number of age 1 fish were well explained by the number of age 0 fish in the previous year and environment indices. These results clarified that the dynamics of this stock is affected by the effect of environment and the dynamics of itself, and thus highlighted the importance of sound stock management for the sustainable and effective use of this stock.