Film forming device and method for forming metal film using the same

A film forming device that avoids a leakage of a liquid electrolyte and a method for forming a metal film using the film forming device are provided. The film forming device to form the metal film includes an anode, a cathode, a solid electrolyte membrane disposed between the anode and the cathode, a solution container that defines a solution containing space between the anode and the solid electrolyte membrane, and a power supply that applies a voltage between the anode and the cathode. The solid electrolyte membrane includes a first surface exposed to the solution containing space and a second surface opposed to the cathode, and is dividable along a division surface having no common point with the first surface or the second surface.