A pressure-sensitive adhesive composition capable of giving a pressure-sensitive adhesive sheet which simultaneously realizes satisfactory holding power, adhesion, and peel resistance in peeling from curved surfaces, while balancing these properties, and has satisfactory heat resistance. The composition comprises the following ingredients: (A) a maleimide crosslinking agent having two or more maleimide groups per molecule; (B) a monomer which, when caused to homopolymerize, gives a homopolymer having a glass transition temperature of −40° C. or lower; (C) a carboxylated monomer copolymerizable with the monomer of the ingredient (B); and (D) a photopolymerization initiator, the maleimide crosslinking agent of the ingredient (A) being contained in an amount of 0.01-2 parts by weight per 100 parts by weight of the sum of the monomers of the ingredients (B) and (C).