Abstract: The present invention provides an adhesive composition which is a primerless urethane-based adhesive and has high adhesive force with respect to a polyolefin-based resin. An adhesive composition according to the present invention is a two-liquid type urethane-based adhesive composition comprising: a main agent which comprises (A) a urethane prepolymer having an isocyanate group at the end thereof, (B) a polyfunctional isocyanate compound having an alkoxysilyl group which can be obtained through a reaction of a silane compound having at least two alkoxysilyl groups in one molecule and a polyisocyanate having an isocyanate group at the end thereof and (C1) a first curing catalyst; and a curing agent which comprises (D) a hydrophobic polyol and (C2) a second curing catalyst.