To actually provide a dice in a three-dimensional shape unfoldable on a two-dimensional plane considered only as imagination and to provide a method for manufacturing the dice.

In this dice having a regular polyhedron shape and unfoldable to consecutive polygonal shapes on a plane, in the case of constituting the regular polyhedron shape, the unfoldable dice in which the boundary area of an inner surface positioned on an inner side is provided with an inclination angle determined by a regular polyhedron and the engaging part of a size not exceeding the respective boundary areas is provided in the boundary area of a predetermined surface is obtained. Such a dice is obtained by injection-molding plastic resin in the molding die corresponding to the developed dice shape.