A mass of graphite is placed into a case, and the case is put into a furnace (step S301). The space in the furnace is heated to produce a porous sintered body of graphite (step S302). Thereafter, the case with the porous sintered body contained therein is removed from the furnace, and put into a cavity in a press (step S303). Then, a molten mass of a metal is poured into the case (step S304), and a punch is inserted into the cavity to press the molten metal into the porous sintered body in the case (step S305).
A composite material having a high thermal conductivity and a small thermal expansion coefficient, which is obtained by impregnating a porous graphitized extrudate with a metal; the composite material having such anisotropy that the thermal conductivity and the thermal expansion coefficient are 250 W/mK or more and less than 4.times.10.sup.-6/K, respectively, in an extrusion direction; and that the thermal conductivity and the thermal expansion coefficient are 150 W/mK or more and 10.times.10.sup.-6/K or less, respectively, in a direction perpendicular to the extrusion direction.
