To provide a non-chlorine-based stripping agent enabling a wire coat such as of formal wire to be stripped in a time equivalent to that in the case with using a methylene chloride-based stripping agent.

This stripping agent is characterized by comprising (A) 60-90 wt.% of formic acid, (B) 5-40 wt.% of a cosolvent and (C) 0-12 wt.% of at least one kind of agent selected from a corrosion inhibitor, thickening agent and surfactant.