To elucidate the temporal response of parasitoids to their host density, we investigated the temporal relationship between the density of the leafroller moth, Eudemis gyrotis (Lepidoptera, Tortricidae), and larval and pupal parasitism in the field. E. gyrotis had overlapping-generations, and the density of larvae and pupae of E. gyrotis varied seasonally. Analysis of the temporal relationship between the density of E. gyrotis and the percentage parasitism revealed a tendency toward positive density-dependent attack by the parasitoid Apanteles sp. (ater-group) (Braconidae) on early-stage E. gyrotis larvae, and inverse density-dependent attack by Goniozus japonicus (Bethylidae) in late-stage larvae. However, no temporal density-dependent attack was observed by the pupal parasitoids Brachymeria excarinata (Chalcididae), B. lasus, and Itoplectis alternans spectabilis (Ichneumonidae). These different responses to host density by the parasitoid species were discussed in terms of the mode of parasitism, the host stages attacked, host-searching behavior, and the effect on the host population.