A method for producing a vinyl chloride-based polymer, the method comprising: a step of polymerizing a vinyl chloride-based monomer in the presence of a vinyl chloride-based first seed particle, a vinyl chloride-based second seed particle, and an emulsifier; and a step of separating, after the polymerizing step, a first vinyl chloride-based polymer and a second vinyl chloride-based polymer which are in a particulate form, wherein the vinyl chloride-based first seed particle has an average particle diameter (D 50), as measured according to the description, of 0.1 μm to 0.4 μm and is produced by adding a vinyl chloride-based monomer, a first emulsifier, and a polymerization initiator to an aqueous medium, performing polymerization, and continuously adding a second emulsifier during the polymerization, the vinyl chloride-based second seed particle has a size, as measured according to the description, of 0.1 μm to 1.0 μm and is produced by adding a vinyl chloride-based monomer, an emulsifier, and a polymerization initiator to an aqueous medium, homogenizing droplets and then performing polymerization, the separation of the particulate first vinyl chloride-based polymer and the second vinyl chloride-based polymer in above is performed by spray drying in a spray dryer, the spray drying is performed under temperature conditions that an inflow temperature to the spray dryer is 130 °C to 220 °C and an outflow temperature from the spray dryer is 40 °C to 80 °C, and a spray speed of the spray dryer is 130 m/s to 180 m/s, the separated first vinyl chloride-based polymer is dried using a fluid bed dryer and the fluid bed dryer is operated at a temperature of 83 °C to 100 °C, and the first vinyl chloride-based polymer has a smaller average particle diameter (D 50), as measured according to the description, than the second vinyl chloride-based polymer. a step of polymerizing a vinyl chloride-based monomer in the presence of a vinyl chloride-based first seed particle, a vinyl chloride-based second seed particle, and an emulsifier; and a step of separating, after the polymerizing step, a first vinyl chloride-based polymer and a second vinyl chloride-based polymer which are in a particulate form, wherein the vinyl chloride-based first seed particle has an average particle diameter (D 50), as measured according to the description, of 0.1 μm to 0.4 μm and is produced by adding a vinyl chloride-based monomer, a first emulsifier, and a polymerization initiator to an aqueous medium, performing polymerization, and continuously adding a second emulsifier during the polymerization, the vinyl chloride-based second seed particle has a size, as measured according to the description, of 0.1 μm to 1.0 μm and is produced by adding a vinyl chloride-based monomer, an emulsifier, and a polymerization initiator to an aqueous medium, homogenizing droplets and then performing polymerization, the separation of the particulate first vinyl chloride-based polymer and the second vinyl chloride-based polymer in above is performed by spray drying in a spray dryer, the spray drying is performed under temperature conditions that an inflow temperature to the spray dryer is 130 °C to 220 °C and an outflow temperature from the spray dryer is 40 °C to 80 °C, and a spray speed of the spray dryer is 130 m/s to 180 m/s, the separated first vinyl chloride-based polymer is dried using a fluid bed dryer and the fluid bed dryer is operated at a temperature of 83 °C to 100 °C, and the first vinyl chloride-based polymer has a smaller average particle diameter (D 50), as measured according to the description, than the second vinyl chloride-based polymer.