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 (In.sub.4Sn.sub.3O.sub.12) detectable through X-ray diffraction and has a SnO.sub.2 solid solution amount in In.sub.2O.sub.3 of 2.3 mass % or more, the SnO.sub.2 solid solution amount being calculated from the precipitated SnO.sub.2 content (mass %) obtained from the ratio between integral diffraction intensity attributed to In.sub.2O.sub.3 (222) and integral diffraction intensity attributed to SnO.sub.2 (110).