Disclosed is a Cu—Fe—P alloy capable of enabling high strength, high electrical conductivity, and excellent softening resistance to coexist. The Cu—Fe—P alloy is suitable for use as a constituent material of a lead frame for a semiconductor device. With the Cu—Fe—P alloy with strength rendered higher by micronizing Fe-containing compounds, when enhancing softening resistance by increasing Sn content so as to exceed 0.5 mass %, at least one element selected from the group consisting of Ni, Mg, Ca, Al, Si, and Cr, in trace amounts, are caused to be additionally contained to thereby check cracking likely to occur at the time of forging and hot rolling in a process of producing the copper alloy, as a result of an increase in the Sn content.