To provide a packaging bag designed so that the central part of the back of the bag is securely and easily torn open from the joined edges so as to form an opening of a predetermined shape and a sufficient size.

The packaging bag A is formed such that its back 3 has the joined back edges 5 in the form of joined palms and longitudinal both ends are sideways sealed. This packaging bag A has a notch 6 in the joined back edges 5 of the storage area of the back 3, the notch 6 serving as a weakening means from which the bag is torn. Series of perforations 8, 8 in the form of perforations, for assisting in tearing the bag are vertically formed in the back 3 of the bag with the joined back edges 5 in between.