To separate sulfur compounds existing in petroleum hydrocarbons such as kerosene, gas oil, etc., greatly efficiently at a low cost without requiring a high temperature and/or high pressure and without needing hydrogen supply or an expensive catalyst.

This method for oxidizing and desulfurizing petroleum hydrocarbons comprises adding ozone to liquid petroleum hydrocarbons, applying a pressure zone, a reduced pressure zone and ultrasonic impact to the petroleum hydrocarbons containing ozone so as to react sulfur compounds container in the petroleum hydrocarbons with ozone to carry out oxidation and desulfurization. Consequently, the petroleum hydrocarbons can efficiently be oxidized and desulfurized with slight energy consumption for separating the sulfur compounds.