base material of the aluminum type / carbon fibers for mounting electronic components.

A base material for mounting electronic components is provided which has a low density and a coefficient of thermal expansion close to that of aluminum and can be processed with ease. The base material essentially consists of aluminum or an aluminum alloy reinforced with carbon fibers with a volume fraction ranging from 0.15 to 0.55, the carbon fibers in the base material being arranged at random on a surface for mounting an electronic component and being arranged in layer in a direction vertical to the above-described surface.