Plating liquid

This plating liquid contains (A) a soluble salt that contains at least a first tin salt, (B) an acid selected from among organic acids and inorganic acids or a salt thereof, and (C) two surfactants, namely an amine-based surfactant (C1) and a nonionic surfactant (C2 and/or C3). The amine-based surfactant (C1) is a polyoxyethylene alkyl amine represented by general formula (1); and the nonionic surfactant (C2 and/or C3) is a condensation product of a polyoxyethylene and a polyoxypropylene represented by general formula (2) or general formula (3). In formula (1), x is 12-18 and y is 4-12. In formula (2), m is 15-30 and (n1 + n2) is 40-50. In formula (3), (m1 + m2) is 15-30 and n is 40-50.