The present invention provides a pressure-sensitive
adhesive composition comprising an
acrylic polymer (a), an acrylic
oligomer (b), a
silane coupling agent having an amino group, and a cross-linking agent, the
acrylic polymer (a) containing, as a main
monomer component, at least one of a (
meth)
acrylic acid alkyl ester containing an
alkyl group having a number of carbons of from 4 to 12 and a (
meth)
acrylic acid alkoxyalkyl ester, and containing 1 to 10 parts by weight of a carboxyl group-containing
monomer as a
monomer component based on 100 parts by weight of the total monomer components constituting the
acrylic polymer (a), the acrylic
polymer (a) having a weight-average molecular weight of from 400,000 to 1,500,000; and the acrylic
oligomer (b) containing a (
meth)
acrylic acid ester as a main monomer component, and containing 1 to 10 parts by weight of a carboxyl group-containing monomer as a monomer component based on 100 parts by weight of the total monomer components constituting the acrylic
oligomer (b), the acrylic oligomer (b) having a weight-average molecular weight of 3,000 or more but less than 6,000, in which the pressure-sensitive
adhesive composition contains 10 to 35 parts by weight of the acrylic oligomer (b) and 0.01 part by weight or more but less than 1.0 part by weight of the
silane coupling agent having an amino group, based on 100 parts by weight of the acrylic
polymer (a). The pressure-sensitive
adhesive composition is excellent in transparency and foaming and separation resistances, does not cause periodical reduction of adhesiveness and dramatically improves adhesion reliability.