As a result of long-term monitoring of the Lepidoptera in Seonheul Gotjawal, Jeju Island, totally 402 individuals of 114 species in 19 families of the Lepidoptera were investigated. The Suborder Rhopalocera appeared in 134 individuals of 26 species in 6 families. Two species are reported for the first time from Korea; Macrocilix mysticata watsoni Inoue, 1958 of the Drepanidae and Mixochlora vittata prasina (Butler,1879) of the Geometridae. Seven species are newly added to the Lepidoptera fauna of Jeju Island; Acleris paradiseana Walsingham, 1900 of the Tortricidae, Dioryctria pryeri Ragonot, 1893, Opsibotys perfuscalis Munroe et Mutuura, 1969, and Sylepta pallidinptalis (Hampson, 1012) of the Pyralididae, Operophera brumata (linnaeus, 1758) of the Geometridae, Lymantiria sakaguchii Matsumura, 1927 of the Lymantriidae, and Dysmilichia genella (Leech, 1889) of the Noctuidae.