A pressure sensitive adhesive composition comprising a copolymer and an isocyanate compound, without a substantial amount of a halogen compound, the copolymer being prepared by copolymerizing radical-polymerizable monomers essentially containing a radical-polymerizable monomer with a carboxyl group, using at least one chain transfer agent selected from a group consisting of .alpha.-pinene, limonene, and terpinolene, in the presence of at least one organic solvent selected from a group consisting of ethyl acetate, acetone, methyl ethyl ketone, and methyl isobutyl ketone, but in the absence of toluene, is disclosed.