To provide a method for manufacturing a bag-like container by which it is possible to cut a manufacturing cost at the time of production by automating the manufacturing of a purse-shaped bag-like container such as to be made of a synthetic resin sheet or the like.

A synthetic resin sheet 7 comprises edge sides, one of which is connected in the sending direction and the other of which is separated and laminated. The other edge side in the sending direction is cut by a required width to form connected belt-like objects 50a, 60a. Further, the other edge side of the synthetic resin sheet 7a is folded inward by a specified width to form an introduction part 15. In addition, notched parts 17 with a specified width are formed at a specified interval in the introduction part 15 and the belt-like objects 50a, 60a are introduced into the introduction part 15. At a position which crosses the sending direction and also passing through the notched parts 17, the mutually corresponding spots of the synthetic resin sheet 7a and the belt-like objects 50a, 60a are welded together and cut by fusion to manufacture the bag-like container with an opening part on the introduction part 15 side.