The invention provides a parakeratosis inhibitor, pore-shrinking agent, or rough skin preventing/amaliorating agent that has a function such as parakeratosis inhibition, pore shrinkage, or rough skin -inhibition/abatement, poses no safety problems such as sensory irritation, and is very safe, and further provides an external composition for skin to which a compound having the above-mentioned function has been added. The parakeratosis inhibitor, pore-shrinking agent, or rough skin preventing/amaliorating agent comprises one or more compounds selected from the group consisting of ²-alanine derivatives and salts thereof. The external composition for skin comprises the one or more compounds selected from the group consisting of ²-alanine derivatives and salts thereof as the above-mentioned parakeratosis inhibitor, pore-shrinking agent, or rough skin preventing/amaliorating agent.本發明提供一種具有不全角化抑制、毛孔縮小、皮膚粗糙的防止．改善等功能，且無感覺刺激等之安全性上的問題，亦即高安全性之不全角化症抑制劑、毛孔縮小劑、皮膚粗糙的防止.改善劑，更者提供一種摻合具有前述功能的化合物之皮膚外用組成物。；本發明係關於1種或2種以上選自β－丙胺酸衍生物及其鹽所成群之化合物所成之不全角化症抑制劑、毛孔縮小劑或者是皮膚粗糙的防止．改善劑。更者，含有1種或2種以上選自前述不全角化症抑制劑、毛孔縮小劑或者是皮膚粗糙的防止．改善劑之β－丙胺酸衍生物及其鹽所成群之化合物所成之皮膚外用組成物。
