PURPOSE: To improve the solderability of a carbon fiber composite metal by adjusting the position of uppermost carbon fibers to below the surface of the metal surface or removing exposed carbon fibers to eliminate the existence of fibers on the metal surface.

CONSTITUTION: Copper-carbon fiber composite metal 1 is composed of copper 3 and carbon fibers 2 whose axes are perpendicular to the plane of the figure. Half exposed carbon fibers 2a exist on surface 4. This composite material is subjected to oxidation treatment in oxygen plasma to allow fibers 2a to disappear as CO2 gas, whereby no carbon fiber is seen on surface 4. Copper 3 of surface 4 is also oxidized, so the oxide layer is preferably removed by heat reduction in hydrogen. Thus, the solderability of composite metal 1 is improved to considerably enhance the soldering strength.