Copper-tungsten alloys used for materials of electrode, electric contacts, package materials for semiconductors, heat sink and their manufacturing methods. The copper-tungsten alloy contains preferably 5 to 30 wt. % of copper, 0.002 to 0.04 wt. % of phosphor, the remaining portion being substantially all tungsten, and it is preferable to contain in these alloys 0.1 to 0.5% of cobalt, nickel or iron or else any combined two out of these three.