In a flat-ended bag made of a flexible film material, two bag wall parts are connected via two longitudinal seams running substantially in a longitudinal direction (z) to form a bag wall that forms a tubular body and has sealing edge strips projecting from the bag wall. The tubular body is closed at both ends, at least one end of the tubular body has a base part disposed substantially perpendicular to the longitudinal axis (z) and serving as a standing surface, and a resealable opening is provided on at least one end of the tubular body. In order to increase the rigidity of the tubular body, the sealing edge strips are folded over onto the bag wall and sealed or glued to the bag wall.