A method for producing a patch having a high skin penetrability and a high pharmaceutical physical properties such as adhesion and cohesiveness, and a long-term storability. The patch is produced by first obtaining an adhesive agent layer composition containing oxybutynin and/or salt thereof as a drug, an acrylic-based polymer and/or a rubber-based polymer as an adhesive base agent, liquid paraffin, an organic acid, and a tackifier; heating the adhesive agent layer composition at a temperature in a range from a melting point of the drug to a temperature higher than the melting point by 10° C. for 2 to 24 hours; and slowly cooling the heated adhesive agent layer composition to obtain the adhesive agent layer comprising the drug at a supersaturated concentration in a dissolved form.