To certainly insulate a valve main body from a ground, and easily assemble the valve main body and a support base to each other, by manufacturing the support base by a non-metallic material having insulation performance, and attaching the support base to the valve main body by a bolt formed of the non-metallic material having insulation performance.

A valve main body 2 is manufactured of a metallic material, corrosion proofing paint is applied to the valve main body 2, and a support base 3 is formed of a non-metallic material having insulation performance such as ceramics and resin, and assembled to the valve main body 2 by bolts 4 formed of the non-metallic material having insulation performance. When a valve 1 is assembled, only the valve main body 2 and the support base 3 are fixed to each other by the bolts 4, and after installation, the valve main boy 2 can be certainly insulated from a ground. Therefore, conventional parts are no more required, such as an insulating packing intervened between the valve main body and the support base and an insulating sleeve arranged around the bolts, thus assembly work can be facilitated.