To provide a method for separating adamantanetriols, capable of simply and efficiently separating the adamantanetriols from a mixture of the adamantanetriols of which the number of hydroxy group is 3 and other adamantanols, such as adamantanemonools, adamantanediols, and adamantanetetraols, of which the numbers of hydroxy groups are each different from 3.

In this method for separating the adamantanetriols, an aqueous solution and/or an aqueous dispersion which contains the adamantanetriols and the other adamantanols of which the numbers of hydroxy groups are each different from 3 are contacted with ethyl acetate at a temperature of ≥40°C to form a two-phase mixture composed of an aqueous phase and an ethyl acetate phase, then the ethyl acetate phase is separated from the aqueous phase, and further the ethyl acetate phase is cooled, so that crystals of the adamantanetriols are deposited. The adamantanols of which the numbers of hydroxy groups are each 3 or less are distributed into the ethyl acetate phase, and the other adamantanols of which the numbers of hydroxy groups are each 4 or more are distributed into the aqueous phase. Because the adamantanemonools and the adamantanediols are not deposited when cooled, the deposited crystals comprise the adamantanetriols with high purity.