Provided is a method for forming a metal film capable of forming a homogeneous metal film having a uniform film thickness by stably ensuring a fluid pressure of an electrolytic solution during film formation. The method places a substrate on a mount base. While sucking a gas between the substrate and a porous film through which the electrolytic solution can pass from a suction port of a suction passage formed on the mount base, the method brings the porous film into contact with the surface of the substrate. The method interrupts the suction passage while the porous film contacts the surface of the substrate. While interrupting the suction passage, the method allows the electrolytic solution to pass through the porous film while pressing the porous film against the surface of the substrate with a fluid pressure of the electrolytic solution and deposits metal from metal ions in the passed electrolytic solution on the surface of the substrate, thereby forming the metal film.