Effects of temperature on the adult emergence process of the Sugi bark borer, Semanotus japonicus LAC0RDAIRE(Coleoptera : Cerambycidae) were studied at the Honjou Nursery of Shimane University from March to April 1987. Total of 515 males and 428 females were collected from 298 sample trees. Although the number of emergence adults was affected by daily changes in temperature, the emergence process was determined by the cumulative temperature above 4.4℃; 129.3 day･degrees (±28.03 s. d.) for males and 146.1 day･degrees(±26.58 s. d.) for females. Whereas males emerged earlier than females, longevity of female in terms of cumulative temperature was as same as that of males; 198.6 day･degrees(±54.33 s. d.) for males and 191.5 day･degrees(±56.96 s. d.) for females.