Disclosed is a built-up type toy having plural parts 10a of polyhedron shape equipped with joining surfaces 11a that are joined with other joining surfaces 11b of other parts 10b. The built-up type toy of the present invention has the parts respectively having magnet portions 10a on the joining surfaces 11a thereof, wherein the magnet portion 100a of the part 10a and the magnet portion 100b on the joining surface 11b of the parts 10b are joined with each other by magnetic force thereof. The built-up type toy of the present invention provides the effects that it is easy to assemble and disassemble, the assemble state is not likely to be demolished easily, and it is helpful to develop the initiative of infant as it can be assemble to various shapes.