PROBLEM TO BE SOLVED: To provide a valve structure in which a valve sheet is not fused to an outer sheet on heat-sealing to a sealed bag.SOLUTION: The right and left sides of three valve constituting sheets 1 and 1 are side-sealed, and opposed valve constituting sheets 1 and 1 are brought into close contact with each other to restrict a fluid from moving. The inside and the outside of a bag body are partitioned by a partition seal, the valve is disposed across the inside and the outside of the bag body, and welded to the bag body by the partition seal. One of the opposed surfaces of the valve constituting sheets is formed of a non-weldable film that is not welded by welding of the side seals and the partition seal. The side seals become non-welded parts to be non-welded in the part of the non-weldable film on the downstream side in the mocing direction of the fluid from the partition seal and side-entering preventive sealed parts that block flows of the fluid into the movement channel from the non-weldable parts are provided continuously to the partition seal on the outer side in the right and left directions of the non-weldable parts.