PURPOSE: To provide a process for production of a composite material which is capable of suppressing the uneven thicknesses of a coating layer and is adequate for production of the composite material having particularly the thin coating layer as the process for production of the composite material which produces the composite material by extruding a sheath metal on the circumference of a core material by an extrusion die and a nipple for supplying a core wire to be fitted into the extrusion die with the from end.

CONSTITUTION: The sheath metal is supplied via grooves 3 to the circumference of the core wire by using the extrusion die 1 provided with the grooves 3 spirally on the circumference of a hole 2 through which the core wire passes. The sheath metal may otherwise be supplied to the circumference of the core wire by using the nipple provided with the grooves spirally on the outside surface of its front end.