PROBLEM TO BE SOLVED: To provide an alkylene oxide adduct favorable in terms of low-temperature fluidity and storage stability and excellent in terms of emulsifying power and thickening performance, and to provide a method of manufacturing the same.SOLUTION: The provided method for manufacturing an alkylene oxide adduct is a method including a step of inducing an addition reaction by feeding, both simultaneously and continuously, ethylene oxide and propylene oxide into an alcohol in the presence of a catalyst. In a case where, following designations of the feeding commencement time and the feeding completion time respectively as T0 and T100, times T1 and T2 between T0 and T100 satisfy relations of T0
