A normal vector or a curvature at each of a plurality of vertexes that are included in data relating to an oral cavity shape including a tooth crown shape of at least one tooth and define the oral cavity shape is acquired. Then, a vertex group that defines the tooth crown shape of the at least one tooth is extracted from the plurality of vertexes based on the acquired normal vectors or curvatures. Further, the extracted vertex group is outputted as tooth crown shape information that specifies a tooth crown portion in the oral cavity shape. Consequently, automatic construction of a database for a tooth crown shape can be implemented.
