An apparatus for producing a three-dimensional shaped product in which metal powder or non-metal powder loaded on a vertically movable table is laminated while being sintered by irradiating electromagnetic waves to each layer, thereby producing a predetermined three-dimensional shaped product and in which the following steps are sequentially repeated, that is: metallic or non-metallic powder is sprayed on a base plate placed on the upper side of a vertically movable table in a shaping tank and having on the surface at least a material which can be adhered to the metallic or non-metallic powder upon solidification of the powder adjacent to the upper side by sintering and on the upper side of the table; a step that the upper-side surface of the thus sprayed powder is subjected to planarization, and electromagnetic waves or electron beams are then irradiated along a layer having a predetermined thickness to a region to be shaped which is located at the uppermost position, thereby forming a sintered layer; and a step that the end part and/or the upper surface where the sintering has been performed are thereafter cut to effect molding, the apparatus for producing a three-dimensional shaped product comprising: - a frame body installed upright on the table, and - two or more of a support projecting horizontally from the frame body and comprising a longitudinal direction and/or a projected streak provided at the top of the frame body and comprising a longitudinal direction which are arranged to support the base plate such that the center of gravity of the base plate is located inside a triangle formed by three locations or a quadrangle formed by four locations inside a region in which the base plate is supported, characterized in that - the two or more of the support and/or the projected streak are installed such that their longitudinal directions cross with each other, and - two or more recesses are provided with longitudinal directions crossing with each other at the back of the base plate in which the two or more of the support and/or the projected streak fit, thereby preventing the base plate from moving horizontally. metallic or non-metallic powder is sprayed on a base plate placed on the upper side of a vertically movable table in a shaping tank and having on the surface at least a material which can be adhered to the metallic or non-metallic powder upon solidification of the powder adjacent to the upper side by sintering and on the upper side of the table; a step that the upper-side surface of the thus sprayed powder is subjected to planarization, and electromagnetic waves or electron beams are then irradiated along a layer having a predetermined thickness to a region to be shaped which is located at the uppermost position, thereby forming a sintered layer; and a step that the end part and/or the upper surface where the sintering has been performed are thereafter cut to effect molding, the apparatus for producing a three-dimensional shaped product comprising: - a frame body installed upright on the table, and - two or more of a support projecting horizontally from the frame body and comprising a longitudinal direction and/or a projected streak provided at the top of the frame body and comprising a longitudinal direction which are arranged to support the base plate such that the center of gravity of the base plate is located inside a triangle formed by three locations or a quadrangle formed by four locations inside a region in which the base plate is supported, - a frame body installed upright on the table, and - two or more of a support projecting horizontally from the frame body and comprising a longitudinal direction and/or a projected streak provided at the top of the frame body and comprising a longitudinal direction which are arranged to support the base plate such that the center of gravity of the base plate is located inside a triangle formed by three locations or a quadrangle formed by four locations inside a region in which the base plate is supported, - the two or more of the support and/or the projected streak are installed such that their longitudinal directions cross with each other, and - two or more recesses are provided with longitudinal directions crossing with each other at the back of the base plate in which the two or more of the support and/or the projected streak fit, thereby preventing the base plate from moving horizontally.