PURPOSE: To produce a nontoxic molded body excellent in thermal stability and plasticizer absorbability without any fish eye by carrying out the suspension copolymerization of vinyl chloride with ethylene in the presence of an oil-soluble polymerization initiator and a specific dispersion stabilizer.

CONSTITUTION: The suspension copolymerization of a mixture of vinyl chloride with ethylene and other copolymerizable monomers is carried out in the presence of an oil-soluble polymerization initiator and a dispersion stabilizer to produce a copolymer having 0.1-25wt.% ethylene composition and 75-99.9wt.% vinyl chloride composition. In the process, a partially saponified polyvinyl alcohol having 70-90mol% saponification degree and 1500-3000 average polymerization degree and a partially saponified polyvinyl alcohol having 70-90mol% saponification degree and 300-1000 average polymerization degree as a dispersion stabilizer, a secondary dispersion stabilizer and a water-soluble cellulosic ester are used in combination. A partially saponified polyvinyl alcohol having 20-65mol% saponification degree and 100-1000 average polymerization degree is used as the secondary dispersion stabilizer.