A metal pre-treating method is provided to remove a film from the metal surface by the relative movement between metal and particle. A metal pre-treating method comprises: a step of removing a film of the meta with the process solution(1); a step of dipping a plurality of particle(22) which does not react to the process solution into the process solution; a step of dipping the metal in the process solution including a plurality of particles; and a step of shaking the metal in the process solution.
