The invention provides a pressure-sensitive adhesive composition, which is prepared by using an alcohol solvent to obtain a high-molecular weight acrylic polymer, and exhibits excellent levels of coating liquid storage stability, stability over time in the adhesiveness, aging suitability, adhesive strength, releasability and heat-resistant holding power, as well as providing a pressure-sensitive adhesive sheet. The pressure-sensitive adhesive composition comprises a specific crosslinking agent and an acrylic polymer with a glass transition temperature of −60 to 0° C. obtained by radical polymerization in an alcohol solvent of an ethylenic unsaturated bond-containing monomer comprising specific amounts of specific monomers, wherein the acrylic polymer contains a low-molecular weight component and a high-molecular weight component with an area ratio therebetween of 65/35 to 80/20, and the monomer has a carboxyl group.