We investigated developmental characteristic of life cycle of the lawn cutworm, Spodoptera depravata (Lepidoptera: Noctuidae), which is one of the most economically damaging pests to grasses. For larval culture the turfgrass, Zoysia japonica (Poales: Poaceae), was provided at 25℃ and 60 ± 5% humidity. Developmental period of each stage was as follows: 4.11 ± 0.19 days for eggs, 25.17 ± 3.02 for larvae, 8.80 ± 0.28 for pupae and 7.57 ± 0.95 for adults. Larvae was grown to 7th instar, unlike pre-existing data, which indicated the final age as the 6th instar. Body length of larvae changed on average from 2.772 mm immediately after hatching to 2.3 cm at 7th instar and head capsule width changed on average from 0.423 mm at 1st instar to 2.82 mm at 7th instar. Pre-period of eggs deposition was 2 days, oviposition period was 4.6 days, average fecundity per female was about 419 eggs, and hatching rate was about 83%.