The soft tissue tumors that occur commonly in newborn infants include palatal and gingival cyst of the newborn, congenital epulis, hemangioma, teratoma, pyogenic granuloma, and irritation fibroma. Such soft tissue tumors in the alveolar ridge of newborns are usually treated by surgical excision. If untreated, they can cause airway obstruction and breathing difficulty due to aspiration. They also cause discomfort during oral feeding. If nasal feeding is tried, since vomitting is impossible, there is a risk of aspiration pneumonia. In this case, a newborn infant visited our hospital with soft tissue tumor as chief complaint, and the infant was treated by surgical excision. It appeared to be similar to pyogenic granuloma and irritation fibroma upon histologic exam. However, it was different from those diseases since multinucleated giant cells were observed and it was congenital. The pathologic process of this neoplasm is not clear. This case is reported, since it is difficult to classify it as a specific disease.