Foreign bodies of fish bones are often visually confirmed, but if they have strayed into the submucosa of the oral cavity or pharynx, they are often difficult to diagnose and remove. We report fish bone foreign matter that had strayed into the tongue. An 87-year-old man complaining of discomfort in the tongue visited an otolaryngologist one month after accidentally swallowing fish bones. Although no foreign body could be confirmed by visual inspection, a foreign body that had entered the tongue was confirmed by computed tomography (CT) and ultrasonography (US) examinations. The foreign body was removed using US under general anesthesia. This case showed that preoperative CT and intraoperative US are clinically useful for the detection and removal of foreign bodies of fish bones that have strayed into the tongue.