To provide a chlorinated polyolefin resin aqueous dispersion excellent in water resistance, adhesiveness, and heat sealability and suitable for use of various coating agents, paint, ink, binder for adhesive, and the like.

The chlorinated polyolefin resin aqueous dispersion includes an acid-modified chlorinated polyolefin resin having a chlorine content of 3 to 70 mass% and a volatile basic compound, and contains substantially no nonvolatile auxiliary agent for converting the resin into an aqueous dispersion, wherein the number-average particle size of the chlorinated polyolefin resin in the aqueous dispersion is 0.3 m or less.