An object of the present invention is to provide a method for purifying a highly pure niobium compound and/or tantalum compound, the method enabling the purification of a highly pure niobium compound and tantalum compound in a simplified manner at a low cost. The object is met by providing a method comprising adding an organic solvent to an aqueous solution containing a niobium compound and/or tantalum compound together with impurities, and then performing extraction via the solution. A niobium compound and/or tantalum compound dissolved in a solution is allowed to precipitate, and said aqueous solution is obtained by dissolving the precipitate in water.