Leiomyoma is a benign tumor arising in smooth muscle. It occurs mainly in the uterus and stomach. However, it rarely occurs in the oral cavity. The patient had noticed swelling of the left side of the buccal mucosa about 7 years previously, but had ignored it. Because the tumor gradually grew larger, he came to our hospital in May 1997. Under the clinical diagnosis of a benign tumor of the left side of the buccal mucosa, we performed enucleation of the tumor under general anesthesia. The histopathlogical diagnosis was vascular leiomyoma. There has been no evidence of recurrence as of 11 months after surgery.