A method of manufacturing a rock bit cone having a substantially conical body on a surface of which a number of teeth are formed is manufactured by pressure-casting with using a casting mold having a molding surface including a cone body defining surface portion and tooth defining surface portions, pouring a molten metal of very hard and low melting point alloy having a melting point of 1040.degree.-1120.degree. C. and Rockwell hardness of 55-65 to the casting mold to centrifugal-cast at least a predetermined area including a tip of each tooth with the hard metal, and pouring a molten tough metal to the casting mold to centrifugal-cast the cone body.