In the method for producing a medical pressure-sensitive adhesive tape or sheet of the invention, a water dispersion-type copolymer solution having a specific composition is used. Therefore, the problem caused by high thixotropy can be eliminated and a pressure-sensitive adhesive layer can be relatively easily formed on a porous substrate by a direct method. In addition, when the medical pressure-sensitive adhesive tape or sheet obtained by the method of the invention is attached to the skin surface, skin adhesion and tube fixing are excellent and at the same time, irritation to skin is low.