The three-dimensional object has a plurality of parts and a joining member that joins these parts. The joining member is independent from the parts. At the time of separating the parts from each other, the joining member is broken by pulling with a certain or greater strength one of the parts from the other in a direction in which one of the part is drawn apart from the other, or by rotating with a certain or greater strength one of the parts relative to the other about the part's center axis.