PURPOSE: To obtain the title resin with markedly reduced residual monomer content, free from any degradation of the resin characteristics, by exposing a vinyl chloride type resin powder prepared by suspension- or emulsion polymerization to a warm air in a specific condition.

CONSTITUTION: A polymer latex is prepared by suspension- or emulsion polymerization, in an aqueous medium, of vinyl chloride or a monomer mixture consisting mainly of vinyl chloride. The resin powder obtained by drying the resulting latex is then brought into contact with a 30W60°C warm air in such a condition that the weight ratio of the air to the powder is 0.05W0.30, thus obtaining the objective resin with markedly reduced residual monomer content.