In the pouch of the present invention in which a pouring spout (3) is formed by means of a heat-sealed part (2) and a non-heat-sealed part (6) by heat sealing plastic films, the inside surfaces of the films that form the portion of the boundary area (Y) between the heat-sealed part (2) and non-heat-sealed part (6) of the pouring spout passage (4) on the side of the non-heat-sealed part (6) contact each other so that no gaps are left in a closed state. Accordingly, even if the pouch is suspended with the pouring spout (3) down following the opening of the pouring spout (3), the leakage of the contents such as a liquid or the like accommodated in the interior of the pouch from the pouring spout (3) a small amount at a time can be securely prevented. The gap-free contact of the inside surfaces of the films can be accomplished by uniformly pressing the films in the boundary area (Y). Furthermore, in the pouch manufacturing method of the present invention, a valve member (103) which restricts the movement of the contents when the pouch is formed is conveyed in accordance with the conveying of web-form body members (101, 102) that form the pouch, and this valve member (103) is welded to the body members (101, 102) in a state in which a sealing preventing member (106) is interposed on the side on which the contents pass through; accordingly, pouches that have a valve function such as a reverse flow preventing function or the like can be continuously manufactured. In addition, in this pouch manufacturing method, in cases where a branched part (254) if formed by folding back at least one side part of a web-form body member (240) at a fold-back line running along the feeding direction of this body member, the body member (240) is guided by a guide so that the pass line length of a portion occupying an arbitrary position is substantially constant from the initiation of fold-back to the completion of fold-back; accordingly, a natural and favorable fold-back can be achieved without generating any slack or wrinkles in the web, so that pouches such as pouches having a branched part (254) can be manufactured with a favorable appearance and commercial properties.