To provide a method for producing propylene oxide from propylene and acetophenone by epoxidation without by-producing styrene, and cumene used as a carrier of oxygen for the epoxidation can be repeatedly used, and acetophenone can be obtained.

The method comprises an oxidation step: cumene is oxidized to obtain cumene hydroperoxide; an epoxidation step: propylene oxide and cumyl alcohol are obtained from the cumene hydroperoxide and propylene; an acetophenone separation step: acetophenone contained in a reaction liquid containing cumyl alcohol is separated and recovered, and cumene is recycled to the oxidation step: and a hydrocracking step: the cumyl alcohol from which the acetophenone is separated in the acetophenone separation step is subjected to hydrocracking to form cumene, and said cumene is recycled to the oxidation step.