A copper alloy of high strength and high electroconductivity which is excellent in characteristics such as strength, electroconductivity and bending formability required as copper alloys for use in electric and electronic parts such as lead frames, terminals and connectors, as well as excellent in the characteristics such as softening resistance, shearing formability. Ag plating property and soldering wettability, the copper alloy comprising: Ni: 0.1 to 1.0% (means mass % here and hereinafter), Fe: 0.01 to 0.3%, P: 0.03 to 0.2%, Zn: 0.01 to 1.5%, Si: 0.01% or less; and Mg: 0.001% or less; in which the relation between the P content and the Si content satisfies the relation: P content/Si content≧10, and the relation for the Ni content, the Fe content and the P content can satisfy following relations: 5≦(Ni content+Fe content)/P content≦7 4≦Ni content/Fe content≦9.