We report a case with a supernumerary or paramolar tooth on the buccal side of the maxillary premolar region. The patient was a 14-year-old boy. Oral findings included a supernumerary tooth with eruption of a portion of the crown at the mesial area of the first molar on the buccal side of the maxillary right second premolar. Dental cone beam computed tomography (CT) revealed that the supernumerary tooth had two cusps, and that it was slightly smaller than the maxillary right second premolar. Concerning the root of the supernumerary tooth, 1/3 of the root apex was incomplete, but the root apex of the maxillary right second premolar was complete. As findings of the extracted tooth, the occlusal-surface appearance of the supernumerary tooth was oval, and the occlusal groove was H-shaped, suggesting a typical tooth resembling the anatomical morphology of the maxillary second premolar. Micro CT images showed that the pulp cavity morphology of the supernumerary tooth had the characteristics of the maxillary premolars.