A method of producing an Indium Tin Oxide powder is described. A method of producing an Indium Tin Oxide powder comprising the steps of: (1) mixing a raw aqueous solution containing indium ions and tin ions and having a proportion of divalent tin ions in the tin ions of 50 wt % or more with an alkali aqueous solution, (2) separating the product into solid and liquid, and (3) calcinating the resulted solid.