The problem of the present invention is to minimize the influence of lactic acid on the property of an adhesive layer, and provide a production method of a patch preparation, which is capable of affording a patch preparation superior in the property of an adhesive layer.A method of producing a patch preparation comprising (a): a step of forming an adhesive layer containing a drug (excluding 2-(4-ethyl-1-piperazinyl)-4-(4-fluorophenyl)-5,6,7,8,9,10-hexahydrocycloocta[b]pyridine and a physiologically acceptable acid addition salt thereof), an acrylic polymer and an organic liquid component compatible with the acrylic polymer, but without containing lactic acid, and (b): a step of adding lactic acid to the aforementioned adhesive layer.
