To provide an adhesive composition which can effectively improve the thermal-peeling-easy properties and the adhesion properties at low temperature at the same time. An adhesive composition comprising a crystalline polymer which comprises polyol units formed from a crystalline polyol as repeating units in the molecule, and a tackifying polymer compatible with said crystalline polymer at a temperature higher than the melting point of said crystalline polymer, wherein the tackifying polymer has an alkyl group with 4 to 8 carbon atoms and a carboxyl group in the molecule, a content of the monomeric units having the alkyl group with 4 to 8 carbon atoms (repeating units derived from a starting monomer having the alkyl group) is 60 to 99 mole % of the whole monomeric units of the tackifying polymer, and the alkyl group includes a butyl group.