To provide a tarpaulin for a vestibule diaphragm having sufficient strength and rigidity, unlikely to dangle, manufacturable easily and at a comparatively low cost, and constructed with a reduced weight.

The tarpaulin for vestibule diaphragm is embodied in a dual structure consisting of an outer piece and an inner piece, wherein the outer piece of tarpaulin is formed on a base cloth having a woven structure formed from warps of polyethylene terephthalate filaments and wefts of polyester filaments, and to this base cloth a soft resin of thermoplastic polymeride is attached firmly by means of fusion attachment with heat.