Disclosed is a transdermally absorbable preparation, in which an adhesive agent produced by crosslinking at least one copolymer is contained in an adhesive layer and the aging period in the production of the adhesive layer can be shortened. The transdermally absorbable preparation comprises a support and an adhesive layer arranged on the support and containing an adhesive agent and a medicinal component. The transdermally absorbable preparation is characterized in that the adhesive agent comprises a resin mixture comprising 100 parts by mass of a specific acrylic copolymer (A) and 0.1 to 30 parts by mass of a specific acrylic copolymer (B) or 0.05 to 2 part(s) by mass of a polyamine compound, and the adhesive layer additionally contains an organic acid.