Abstract: A copper alloy having superior thermal conductivity comparable to that of conventional materials, can be produced at low cost. An oxygen free copper, a base material of a Cu—B alloy were melted in vacuo by a casting method, B and at least one element selected from Mg, Ni, Co, Al, Si, Fe, Zr, and Mn are added into the molten metal wherein the content of each element or the alloy of Ni—B, Fe—B, Cu—Mg, and so forth becoming the predetermined content. This alloy is cast into an ingot of 12 mm square, heated at 600 to 900° C. for 1 hour, and the cast was rolled to be 3 mm by hot rolling. After these steps, heat treatment at 600 to 900° C. was provided and processed into predetermined shape.

Abstract: A high strength copper alloy is made of a prescribed material composed of Cu and inevitable impurities as well as titanium (Ti) at 0.1 to 4 weight percent, wherein it is possible to further include at least one of Ag, Ni, Fe, Si, Sn, Mg, Zn, Cr, and P at a prescribed weight percent ranging from 0.01 to 2 in total. In a manufacturing method, the material is subjected to cold rolling, precipitation treatment, and additional cold rolling sequentially, wherein the reduction rate of the additional cold rolling is set to 3% or more, and the total reduction rate of the cold rolling and the additional cold rolling ranges from 15% to 50%, so that a ratio of yield strength versus tensile strength is set to 0.9 or more. In addition, it is possible to perform stress relaxation annealing after the additional cold rolling upon heating of the material for a prescribed time.