To provide an aqueous dispersion of a composite resin composition for an adhesive, capable of forming an adhesive composition having excellent cohesive force, high bonding force to a polyolefin material to be bonded and a good waterproof property.

This aqueous dispersion of the composite resin composition for the adhesive is obtained by polymerizing (A) a radically polymerizable ethylenically unsaturated monomer in an aqueous medium consisting of (B) an aqueous dispersion of a polyolefin, a surfactant, a polymerization initiator and water as essential components.