The invention provides an indium oxide-tin oxide powder which can be produced at low cost and which can provide a high-density sputtering target having a prolonged target life, and a sputtering target employing the powder. The indium oxide-tin oxide powder containing an In—Sn oxide as a predominant component is characterized in that the oxide powder contains no compound oxide (In4Sn3O12) detectable through X-ray diffraction and has a SnO2 solid solution amount in In2O3 of 2.3 mass % or more, the SnO2 solid solution amount being calculated from the precipitated SnO2 content (mass %) obtained from the ratio between integral diffraction intensity attributed to In2O3 (222) and integral diffraction intensity attributed to SnO2 (110).