Production process and cement dispersing agent for polycarboxylic acid polymer for a cement dispersant

To improve the production efficiency of the polycarboxylic acid cement dispersant. At least one or more monomers represented by A Formula 1, when producing the polycarboxylic acid cement dispersant by polymerizing at least one or more monomers represented by Chemical Formula 2 to, to adopt a light polymerization. Further, by promoting the polymerization reaction at a high concentration under the conditions of the monomer, to obtain a solvent content less polymer composition. Specifically, under conditions concentrations of 50 to 100 mass% of the monomer relative to the total weight of monomer and solvent, the steps of polymerizing the monomer and cooling the formed polymer, solidification a step of a method for producing a powdery polycarboxylic acid cement dispersant comprising a step of pulverizing the solidified polymer.