1. A double curtain device wherein a curtain provided with punched patterns is connected at the respective ends with a main winding shaft and auxiliary winding shaft both rotatably provided between right and left supporting cases, a balance weight shaft is inserted and held in a folded part of the curtain so as to tension the curtain, a joint is slidably fitted to the main winding shaft (2) so that the length of the main winding shaft may be adjustable, said auxiliary winding shaft is formed by fitting a small diameter tube provided with an axial groove cut on one side into a large diameter tube provided also with an axial groove cut on one side, many annular concave grooves and annular convex parts fitting them are formed respectively in the fitting parts of the small diameter tube and large diameter tube so that the length of the auxiliary winding shaft may be adjustable, a winding chain is hung on a chain wheel secured to one end of the auxiliary winding shaft and engaging holes for said winding chain are made as opposed to the chain on the lower surface of the supporting case.