The present invention provides a simple method for producing a medical/cosmetic sheet that is excellent in adhesion to skin or the like and sense of wearing, and is capable of releasing a functional component gradually and supplying it continuously to a treatment area or the like, and a medical/cosmetic sheet produced by this production method. Provided is a method for producing a medical/cosmetic material including a step of shaping a raw material containing a water-soluble salt of a first polyanionic polysaccharide having a viscosity-average molecular weight of 10,000 or lower, and a water-soluble salt of a second polyanionic polysaccharide having a viscosity-average molecular weight of 50, 000 or higher, and thereby obtaining a water-soluble shaped body. A medical/cosmetic material produced by this production method is also provided.