PURPOSE: To provide an adhesive having excellent bond strength, containing a polyester copolymer composed of a dicarboxylic acid unit consisting of a terephthalic acid residue and a glycol unit consisting of two specified kinds of diol residues as an active component.

CONSTITUTION: An adhesive contains, as an active component, a polyester copolymer composed of a dicarboxylic acid unit consisting of a terephthalic acid residue and a glycol unit consisting of 99W50mol% of a 1,6-hexanediol residue and 1W50mol% of a 2-methyl-1,3-propanediol residue. This polyester copolymer has a low melting point and a moderate crystallinity and gives an adhesive compsn. having excellent bond strength.