A purification method in which the amount of an inorganic adsorbent to be used is small and the time for the separation of a polyether compound from the inorganic adsorbent by filtration can be shortened. By the method, a purified polyether compound reduced in the content of metals derived from a composite metal cyanide complex catalyst can be obtained. An alkylene oxide is subjected to ring-opening polymerization reaction with an initiator having at least one hydroxy group in the presence of a composite metal cyanide complex catalyst to synthesize a polyether compound. A powder of an inorganic adsorbent at least 50 vol.% of which is accounted for by fine particles having a particle diameter of 26 µm or smaller and at least 90 vol.% of which is accounted for by fine particles having a particle diameter of 44 µm or smaller is then added to the polyether compound to adsorb the metals derived from the composite metal cyanide complex catalyst onto the powder. The powder is separated from the polyether compound to purify the polyether compound.
