Film forming apparatus

A film forming apparatus comprising:

• a cylindrical evaporation source that is composed of metal and includes an internal space for accommodating a workpiece;
• an electrode arranged in the internal space of the evaporation source;
• and
• a gas passage that supplies gas to the internal space of the evaporation source from a space outside the evaporation source and includes an end portion located in the internal space, wherein
• the film forming apparatus is configured to form a film by depositing, on the workpiece, metal ions are released from the evaporation source by arc discharge generated between the evaporation source and the electrode,
• the end portion of the gas passage includes
• a first section composed of a first material, and
• a second section composed of a second material, and
• the first material and the second material have different thermal expansion coefficients.