An extrusion-molding device for producing a green honeycomb molded body with a cell structure, the device comprising: a housing with a flow passage for transporting a paste raw material composition; a screw (2A, 2B) provided upstream of the flow passage for kneading the raw material composition and transporting it downstream; a die provided downstream of the flow passage and having slits corresponding to the shape of the cell structure of the green honeycomb molded body; a resistance tube for connecting the flow passage and the die; and a fragmenting board (5; 7) provided between the screw (2A, 2B) and the die, having through-passages (6; 7a) through which the raw material composition passes from an upstream end side to a downstream end side thereof, wherein the through-passages (6; 7a) comprise: upstream channels (6A; 7A) composed of a plurality of flow passages extending downstream from the upstream end side of the fragmenting board (5; 7); and downstream channels (6B; 7B) extending up to the downstream end side of the fragmenting board (5; 7) and having flow passage cross-sectional shapes different from those of the upstream channels (6A; 7A), characterized in that the upstream channels (6A; 7A) are composed of a plurality of flow passages (6a; 7a) extending downstream essentially straight from the upstream end side of the fragmenting board (5; 7), and the downstream channels (6B; 7B) are composed of a plurality of slits (S; 7b) each connected to the plurality of flow passages (6a; 7a). a housing with a flow passage for transporting a paste raw material composition; a screw (2A, 2B) provided upstream of the flow passage for kneading the raw material composition and transporting it downstream; a die provided downstream of the flow passage and having slits corresponding to the shape of the cell structure of the green honeycomb molded body; a resistance tube for connecting the flow passage and the die; and a fragmenting board (5; 7) provided between the screw (2A, 2B) and the die, having through-passages (6; 7a) through which the raw material composition passes from an upstream end side to a downstream end side thereof, wherein the through-passages (6; 7a) comprise: upstream channels (6A; 7A) composed of a plurality of flow passages extending downstream from the upstream end side of the fragmenting board (5; 7); and downstream channels (6B; 7B) extending up to the downstream end side of the fragmenting board (5; 7) and having flow passage cross-sectional shapes different from those of the upstream channels (6A; 7A), characterized in that the upstream channels (6A; 7A) are composed of a plurality of flow passages (6a; 7a) extending downstream essentially straight from the upstream end side of the fragmenting board (5; 7), and the downstream channels (6B; 7B) are composed of a plurality of slits (S; 7b) each connected to the plurality of flow passages (6a; 7a). wherein the through-passages (6; 7a) comprise: upstream channels (6A; 7A) composed of a plurality of flow passages extending downstream from the upstream end side of the fragmenting board (5; 7); and downstream channels (6B; 7B) extending up to the downstream end side of the fragmenting board (5; 7) and having flow passage cross-sectional shapes different from those of the upstream channels (6A; 7A), upstream channels (6A; 7A) composed of a plurality of flow passages extending downstream from the upstream end side of the fragmenting board (5; 7); and downstream channels (6B; 7B) extending up to the downstream end side of the fragmenting board (5; 7) and having flow passage cross-sectional shapes different from those of the upstream channels (6A; 7A),