Abstract: A method includes a slurry preparing process of preparing a ceramic powder slurry, an impregnating process of impregnating the slurry into an inorganic fiber sheet to form an impregnated sheet, a sheet winding process of winding an impregnated sheet around a core to form a sheet-wound core, a pressing process of disposing the impregnated sheet between a first mold and a second mold opposed to each other and interposing a spacer therebetween at a portion where the impregnated sheet is not positioned, and then clamping the first mold and the second mold with a first fastener to come close in a direction facing each other, thereby applying pressure to the impregnated sheet, a drying process of heating and drying the impregnated sheet, and a firing process of firing the sheet after drying.