The present invention relates to a method of preparing a vinyl chloride-based polymer, which may prepare a vinyl chloride-based polymer with excellent surface properties by adjusting a foam level generated during a polymerization reaction to an appropriate value, a vinyl chloride-based polymer prepared thereby, and an apparatus for preparing a vinyl chloride-based polymer which may prepare the vinyl chloride-based polymer. The method of preparing a vinyl chloride-based polymer according to the present invention may prepare a vinyl chloride-based polymer with excellent surface properties, for example, fewer occurrences of fish-eyes and excellent transparency, by performing a polymerization reaction while maintaining the level of a foam generated during the polymerization reaction at an appropriate value.