A composite structure comprising two polytetrafluoroethylene porouslayers and a framework structural member having a plurality of gaps oropenings, the framework structural member being disposed between thetwo polytetrafluoroethylene porous layers, wherein the compositestructure is structured such that the polytetrafluoroethylene porouslayers are united together by being adhered with each other through thegaps or openings of the framework structural member and such that therespective polytetrafluoroethylene porous layers (A1) and (A2) are unitedwith the framework structural member closely along the surfaces of therespective constituent elements of the framework structural member insuch a manner as to wrap the respective elements. The method ofmanufacturing the composite structure is characterized in that itincludes a step of applying pressure through a mass of fine particles.
