As demand for Tenebrio molitor increases in animal feed market, improvement of mass-rearing indoor system became more crucial. This study is aimed at establishing the technology for conserving genetic resource of Tenebrio molitor, and increasing the technology utilization. This year, in advance, this experiment was designed for examining the developmental characteristics of eggs and larvae. To research the developmental characteristics under different temperatures, eggs, larvae and papae were treated at 17.5, 20, 22.5, 25, 27.5 and 30°C. At 25°C, larvae were exposed to various photoperiod conditions, LD 14:10, 12:12, and 10:14. The results show that the temperature range which affected hatching was 15~32.5°C. To achieve 70 percent or higher hatching rate 17.5~27.5°C was required. Furthermore, hatching occurred within 10 days, when the eggs were treated in 22.5~27.5°C. In regard of larval development, shorter developmental period, and higher pupation and eclosion rates were observed in 25~27.5°C. The shortest larval period was recorded at 14L:10D. At 10L:14D, in contrast, pupae showed the lowest chance of eclosion. Overall, larval development was optimal in long-day condition.