Titanium-copper alloy having plating layer

A titanium-copper alloy comprising a base material and a plating layer provided on a surface of the base material, wherein the base material contains 1.5% by mass to 5.0% by mass of Ti, with a balance consisting of copper and unavoidable impurities, and the plating layer is selected from the group consisting of (a) a Co plating layer and (b) a Co—Ni alloy plating layer having a Co content of at least 20% by mass, wherein a thickness of the plating layer is 0.02 μm to 1.0 μm, and a solder adhesion strength before heating measured by joining a strip of the titanium-copper alloy with a solder on an area of 30 mm×15 mm at a joining temperature of 245° C.±5° C. and performing a 180° peeling test is 0.5 N to 21.1 N.