There is provided according to the present invention a process for producing fluoromethyl hexafluoroisopropyl ether ((CF3)2CH—O—CH2F), including: reacting bisfluoromethyl ether with hexafluoroisopropyl alcohol in a solvent substantially immiscible with hydrogen fluoride in the presence of a catalytic amount of a strong acid selected from sulfuric acid and any other acids stronger in acidity than sulfuric acid. The process of the present invention enables industrial production of the fluoromethyl hexafluoroisopropyl ether without using hydrogen fluoride or a large amount of sulfuric acid and thereby without causing a large amount of waste as a by-product.