There is provided a bag with a pouring spout that can surely improve opening properties and shape retention of a spout port part without the need to render the spout port part bulky, can prevent clogging of the spout port part caused by flexing of the spout port part, and can reliably and easily spout the contents of the bag. The bag with a pouring spout comprises a narrow-width spout port part provided at one end of a laminated film bag, characterized in that in the region of the spout port part, a tape shaped sheet material, which has been cut into a desired length, is applied to the inner surface of at least one of the laminated films provided on both respective sides of the bag.