A pressure-sensitive adhesive composition contains (a) an acrylic polymer containing an alkyl (meth)acrylate whose alkyl group has from 4 to 12 carbon atoms, as a monomer major component and from 1 to 10 parts by weight, based on 100 parts by weight of the whole of the monomer components, of a carboxyl group-containing monomer as a monomer component and having a weight average molecular weight of from 500,000 to 900,000; and (b) an oligomer containing an ethylenically unsaturated monomer, in which a homopolymer formed therefrom has a glass transition temperature of from 60 to 190 C. and which has a cyclic structure, as a monomer major component and from 1 to 10 parts by weight, based on 100 parts by weight of the whole of the monomer components, of a carboxyl group-containing monomer as a monomer component and having a weight average molecular weight of from 3,000 to 6,000.