A storage bag is disclosed having a simple structure and capable of discharging gas generated by contents and capable of preventing the contents from leaking. In the storage bag closed by heat sealing, a pressure sensitive adhesive is previously applied to an arbitrary heat portion. The portion applied with the pressure sensitive adhesive is heat sealed in a state in which the portion is divided, and a gas venting air passage is formed as a non-heat seal portion in an intermediate portion of the heat sealed portion.