To provide a method for producing propylene oxide by which whole volume of a reactor of an epoxidation process can effectively be utilized and a reaction proceeds efficiently and the deterioration of a catalyst caused by locally accumulating the heat of the reaction can be prevented and by-products can be suppressed.

This method for producing propylene oxide comprises a process for obtaining propylene oxide and cumyl alcohol by reacting cumene solution containing cumene hydroperoxide and an excess amount of propylene in a liquid phase in the presence of a solid catalyst and a process for separating and recovering unreacted propylene contained in the reaction solution of the epoxidation process and recycling the recovered propylene to the epoxidation process as a raw material. In the method, total concentration of 1-3C saturated hydrocarbon compound and ethylene in propylene recycled from the propylene recovery process to the epoxidation process is kept to ≤30 wt.%.