To provide a method for producing copolymer dispersion of high stability, low viscosity and high concentration by carrying out suspension polymerization followed by emulsion polymerization in no need of additive operation as polymer concentration after the completion of polymerization reaction.

The production process for copolymer dispersion comprises (1) the first step in which a monomer mixture (A) comprising 0.1-10 wt.% of an ethylenically unsaturated carboxylic acid monomer and 90-99.9 wt.% of other copolymerizable monomers is suspension-polymerized by using an oil- soluble polymerization initiator and (2) the second step in which another monomer mixture (B) comprising 0.1-10 wt.% of an ethylenically unsaturated carboxylic acid monomer and 90-99.9 wt.% of other copolymerizable monomers is added to the polymer dispersion together with an emulsifier and a water-soluble polymerization initiator to effect the emulsion polymerization.