Provided is a transdermal absorption preparation having superior drug skin permeability, which can uniformly disperse the drug in the preparation and maintain the uniform dispersion state of the drug. A transdermal absorption preparation having a plaster layer containing a drug, a polymer and a pH adjuster, in which the aforementioned polymer contains a polymer having a particular glass transition temperature of 30 DEG C - 200 DEG C, and the surface of the plaster layer has a pH of 6.7 - 10.0.本發明之課題在於提供不僅具有優異的藥物皮膚透過性，且可使製劑內之藥物均一分散並且持續維持該藥物之均一分散狀態之經皮吸收型製劑。解決手段係於具有包含藥物、聚合物及pH調節劑之膏體層之經皮吸收型製劑中，前述聚合物包含具有30℃～200℃之特定玻璃轉移溫度之聚合物，進而膏體層表面具有6.7～10.0之範圍的pH。
