A film deposition device (1A) of a metal film (F) includes a positive electrode (11), a solid electrolyte membrane (13), and a power supply part (14) that applies a voltage between the positive electrode (11) and a base material (B) to be a negative electrode. The solid electrolyte membrane (13) allows a water content to be 15% by mass or more and is capable of containing a metal ion. The power supply part (14) applies a voltage between the positive electrode and the base material in a state where the solid electrolyte membrane is disposed on a surface of the positive electrode such that metal made of metal ions contained inside the solid electrolyte membrane (13) is precipitated on a surface of the base material (B).