To provide a seal and/or diaphragm of an apparatus to be used in the fuel supply system of a vehicle, meeting the requirements of the heat resistance, oil resistance, and the resistance against bending and also gas impermeability, which can manage without undergoing any special intensifying process for the bonding force, compared with a conventional rubber component item of such a structure that a nylon covering is provided on an NBR rubber material.

Fluorosilicone rubber or hydrin rubber is used as a base material A of the seal and/or diaphragm, while nylon or fluororesin is used as a covering material B. Any of the base materials may be combined with any of the covering materials.