A manifold comprises a base material section made from an amorphous resin, a solenoid valve section including a plurality of solenoid valves made up of valve bodies, and a coupling section including a plurality of pipe couplings. The overall surface of the base material section is covered in a surrounding fashion without pinholes by a protective film, which is a dense layer film made from a chemically stable material. The manifold is surrounded by a protective box as necessary.