Provided are a polyhedron of which the upper width is narrower than the lower width, a manufacturing method therefor, and a photoelectric conversion device comprising the same. The photoelectric conversion device comprises: a substrate; a polyhedron disposed on the substrate and of which the upper width is narrower than the lower width; and a semiconductor layer disposed on the polyhedron. The photoelectric conversion device to which the polyhedron, of which the upper width is narrower than the lower width, is applied can have improved photoelectric conversion efficiency due to structural characteristics of the polyhedron.