To provide a water-soluble film having excellent solubility, a packaging bag using the water-soluble film, a content release body using the water-soluble film, and a method for producing a water-soluble film. It is a water-soluble film prepared by film-forming a raw material containing a polyvinyl alcohol-based resin and a bisulfite. A bisulfite is added to the raw material containing the polyvinyl alcohol-based resin. Owing to this, the decrease in solubility of the water-soluble film is suppressed even though the raw material is maintained in a heating state for a predetermined time. This effect is the effect characteristic in a bisulfite, and is the effect that is not obtained in the case where a sulfite is used.