Method for purifying a high-purity niobium compound and / or tantalum compound

Providing a purifying method more simply and high purity niobium compound at a low cost and / or high-purity niobium compound capable of performing the purification of the tantalum compound and / or tantalum compound. From a solution containing niobium and / or tantalum, to produce a niobium compound using the obtained crystals, melt or filtrate by crystallization and / or tantalum compounds, high purity niobium compound and / or tantalum using a difference in their solubility and performing separation of the compounds.