PURPOSE: To obtain carrier for single catalyst having improved purification ability easily with good productivity by blocking temporarily part of discharge parts when ceramic carrier having many parallel gas passages is molded by extrusion, and forming communicating passages between gas passages.

CONSTITUTION: Ceramic material 1 which is pressure-fed from a pump 2, is passed between fixed rods 5 and pushed out from discharge ports 7 and forms isolation walls 9 constituting many gas passages 8 having square cross section. Immediately behind the discharge port 7, a communicating passage former 11 provided with thin long plate-form discharge port blockade member 10 is supported freely rotationally on a extruder 3 by means of a bolt 12, and rotated at a constant speed by means of a gear 13. Part of the discharge ports 7 is temporarily blocked by the discharge port blockade member 10. As a result, ceramic material which is pushed out from the extruder 3, is not pushed out from the discharge ports 7 which are blocked by the blockade member 10, and the isolation walls 9 in this part become extinct, and a communicating passage 14 between the gas passages is formed.