Solitary keratoacanthoma is a rather common, rapidly growing neoplasm appearing mainly on sun-exposed areas of the skin in elderly, light-complexioned person. The majority of these lesions occur on the face, forearms, and hands. It is thought that intralesional methotrexate is effective as nonsurgical treatment of keratoacanthoma. A 85-year-old female presented with history of a rapidly growing 1.5cm-sized mass on the right submandible for 2 months. Histopathologic examination showed eosinophilic and glassy cell within shell and resulted in diagnosis of keratoacanthoma. We performed methotrexate injection with 0.1cc (50mg/2cc) each, four times in a row, with an interval of 3 weeks between inspections. After 6 weeks of treatment, the skin lesion had almost completely resolved. We report a case of keratoacanthoma which was successfully treated by intralesional methotrexate. Intralesional methotrexate can promote rapid improvement so in patient with cosmetic concern, we recommend intralesional methotrexate as nonsurgical treatment of keratoacanthoma.