The invention provides a pressure-sensitive adhesion composition, a pressure-sensitive adhesive, and a pressure-sensitive adhesion sheet with excellent durability when suitable for optical members such as polarizers or the like. In order to solve the above problem, a pressure-sensitive adhesion composition is provided comprising a monomeric unit as a formed polymer, a monomeric (methyl) acrylate polymer (A) over 1.5% by weight and having hydroxyl, isocyanate series cross-linking agent (B), silane coupling agent (C) having sulfydryl used as a functional group reacting with organic materials, and an active energy line solidification ingredient (D).