Eosinophilic ulcer (EU) is a rare self-limiting oral condition, frequently occurring on the tongue and appearing as an ulcer with elevated induration of the surrounding tissue. Consequently, there is risk of misdiagnosis as carcinomatous ulcer. We describe a 30-year-old man with a painful ulcer on the tongue, which reappeared one and a half months after healing. First, a lesion developed on the dorsum of the tongue. The lesion healed without active treatment after 1 month. However, two lesions were then observed on the right ventral aspect of the tongue. Histopathological examination of the lesions showed ulceration and inflammatory deterioration with distinct eosinophilic infiltration extending into the deep underlying connective tissue and muscle fibers. Immunohistochemical analysis revealed a large number of CD30-positive large atypical cells among inflammatory cells. As a result, an eosinophilic ulcer was diagnosed. The recurrent lesions also healed without active treatment, similar to the primary lesion.