A method for producing a patch comprising a support layer and an adhesive agent layer arranged on at least one surface of the support layer, the method comprising:a step A of obtaining an adhesive agent layer composition comprising 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 tackifiera step B of heating the adhesive agent layer composition at a temperature in a range from a melting point (°C) of the drug to a temperature higher than the melting point by 10°C for 2 to 24 hours anda step C of cooling the heated adhesive agent layer composition to a temperature lower than the melting point of the drug at an average rate of temperature drop of 1 to 20°C/hour, thereby obtaining the adhesive agent layer comprising the drug at a supersaturated concentration in a dissolved form.
