Graphite is placed in a case, and the case is set in a furnace. The interior of the furnace is subjected to sintering to produce a porous sintered member of graphite. After that, the case with the porous sintered member therein is taken out of the furnace, and is set in a recess of a press machine. Subsequently, molten metal of metal is poured into the case, and then a punch is inserted into the recess to forcibly press the molten metal in the case downwardly. Open pores of the porous sintered member are infiltrated with the molten metal of the metal by the pressing treatment with the punch.