To provide a method for producing dimethyl ether from a combustible waste by gasifying the combustible waste, deashing and desalting the obtained synthetic gas and directly desulfurizing hydrogen sulfide, etc., in gas.

Dimethyl ether is produced from a synthetic gas obtained by gasifying a combustible waste. The process comprises a gasification step to gasify the waste by the thermal decomposition and partial combustion of the combustible waste in a gasifying furnace, a dedusting step to remove unburnt carbon and ash in the synthetic gas flow discharged from the gasification step and simultaneously carry out the desalting treatment, a desulfurization step to directly desulfurize the sulfur in the dedusted synthetic gas in the presence of a catalyst and a dimethyl ether synthesis step to synthesize dimethyl ether from the purified gas desulfurized in the desulfurization step.