Abstract: This foldable bag (A) includes a container main body (B) having: a set of foldable surfaces (5) positioned on a front surface and a rear surface when the foldable bag is in a folded state; inner bottom pleats (6) formed from one longitudinal end side (M1) of each of the foldable surfaces toward an inner other end side, and having a width corresponding to a bottom gusset (20); a plurality of sets of top inner pleats (7,8) formed from the other longitudinal end side (M2) of each of the foldable surfaces toward an inner one end side, and having pleat widths that become gradually narrower toward the inner-facing side. After use, the container main body can be flipped over and folded into a flat rectangular shape by tensioning bundling end parts (C), at which side end parts (4) are sealed, in a direction pulling the bundling end pails apart.

Abstract: This foldable bag (A) includes a container main body (B) having: a set of foldable surfaces (5) positioned on a front surface and a rear surface when the foldable bag is in a folded state; inner bottom pleats (6) formed from one longitudinal end side (M1) of each of the foldable surfaces toward an inner other end side, and having a width corresponding to a bottom gusset (20); a plurality of sets of top inner pleats (7,8) formed from the other longitudinal end side (M2) of each of the foldable surfaces toward an inner one end side, and having pleat widths that become gradually narrower toward the inner-facing side. After use, the container main body can be flipped over and folded into a flat rectangular shape by tensioning bundling end parts (C), at which side end parts (4) are sealed, in a direction pulling the bundling end parts apart.