A steel plate for paint use which contains C (0.12% or less), Si (1.0% or less), Mn (2.5% or less), P (0.05% or less), S (0.02% or less), and Cr (0.05% or less), Cu (0.05-3.0%), Ni (0.05-6.0%), Ti (0.025-0.15%), and Cu+Ni (0.50% or more), with P_CM being 0.23% or less, in terms of mass %. Said steel plate may contain at least one additional component selected from B (0.0005-0.0030%), Al (0.05-0.50%), Ca (0.0001-0.05%), Ce (0.0001-0.05%), La (0.0001-0.05%), Nb (0.002-0.05%), V (0.01-0.10%), Zr (0.002-0.05%), and Mo (0.05-0.5%), in terms of mass %. This steel plate provides good weldability as well as good painting durability in a salt-polluted environment.