To provide a pressure-sensitive adhesive which is used for a surface protection sheet, has a good high-speed peelability, does not cause zipping, shows little change of peeling force by peeling speed, does not cause floating or peeling when it is hot, and is durable.

A cross-linkable composition is provided which comprises component (A) which is a (meth)acrylic polymer having a glass transition temperature of -40°C or lower and prepared by copolymerizing at least an alkyl (meth)acrylate and a functional-group-containing monomer, component (B) which is a (meth)acrylic polymer having a glass transition temperature of 80°C or higher and mainly comprising a (meth)acrylic ester, and component (C) which is a cross-linker, the quantity of component (B) being 5-20 pts.wt. based on 100 pts.wt. component (A). The composition is subjected to cross-linking reaction so as to have a gel fraction of 80% or higher, thus giving the pressure-sensitive adhesive for a protection sheet.