To provide a fine carbon fiber/metal composite material having high mechanical strength, a high thermal conductivity and a low coefficient of thermal expansion and suitable as a substrate for an electronic device.A fine carbon fiber/metal composite material, which is prepared by pressure impregnating a molded product containing fine carbon fibers having a fiber diameter of from 0.5 to 500 nm and a fiber length of at most 1,000 .mu.m, having a multilayer structure wherein cylindrical carbon layers overlap one another, and having a hollow-structured central axis, with aluminum, magnesium, copper or an alloy of such a metal, by molten metal forging.