A tin-plated copper terminal material in which on a substrate made of copper or copper alloy, a nickel-or-nickel-alloy layer, a copper-tin alloy layer, and a tin layer are laminated in this order; in this material, the tin layer has an average thickness 0.2 μm to 1.2 μm inclusive; the copper-tin alloy layer is a compound alloy layer in which Cu6Sn5 is a main ingredient and part of copper in the Cu6Sn5 is substituted with nickel, and an average crystal grain size is 0.2 μm to 1.5 μm inclusive; part of the copper-tin alloy layer appears on a surface of the tin layer and tin solidification parts exist like islands; and the tin solidification parts have an average diameter 10 μm to 1000 μm inclusive in a direction along the surface of the tin layer and an area ratio to the surface of the tin layer 1% to 90% inclusive.