To easily attach auxiliary members of a bag body made of resin film.

A bag body 1 is formed of a resin film comprising an opening 1b at the top end, blocked both side ends, and a bottom end part 1a. On the surface side of the bag body 1, auxiliary members 2 and 3 made of the resin film are superposed over the whole width. The auxiliary members 2, 3 and both side ends of the bag body 1 are integrally connected by heat sealing. The bag body 1 is formed by folding back a single resin film so as to superpose the top and rear faces in two layers, making the folded end to be a bottom end part 1a, and connecting superposed ends 1e at both sides are connected by heat sealing. Both end sides of the bag body 1 are covered with the auxiliary member 2 so as to cover the bottom end part 1a of the bag body 1 and the top and rear sides at the bottom end part 1a, so that the bottom end part 1a of the bag body 1 is formed into a double bottom by the bag body 1 and the auxiliary member 2. Further, the auxiliary member 3 is formed into a band-like shape and the auxiliary member 3 is superposed on the peripheral edge of one face side of at least either the top face or the rear face of the opening 1b of the bag body 1 or on a position close to the peripheral edge so as to make the auxiliary member 3 to be a handle of the bag body 1.