The present invention is a pressure sensitive adhesive comprising: an ingredient (A) which is a copolymer of a carboxyl group-containing monomer and (meth)acrylic ester； and an ingredient (B) which is a copolymer of a pyrrolidone group-containing monomer and (meth)acrylic ester, wherein the ingredient (A) is crosslinked by at least one crosslinking agent selected from the group consisting of a metal chelate compound, a metal oxide and a metal hydroxide, and the blending ratio of the ingredient (A) is 70 to 90 weight % based on the total amount of the ingredient (A) and ingredient (B).
