An Sn—Zn alloy solder having a composition comprising 7 to 10 mass % of Zn, 0.075 to 1 mass % of Ag, and 0.07 to 0.5 mass % of Al; further comprising one or two components selected from 0.01 to 6 mass % of Bi and 0.007 to 0.1 mass % of Cu; and optionally comprising 0.007 to 0.1 mass %, with the balance being Sn and unavoidable impurities. The solder has the same processability, service conditions, and connection reliability as conventional Sn-37 mass % Pb eutectic solder, and does not contain the biologically harmful lead.