Sb—Te-based alloy sintered compact sputtering target

An Sb—Te-based alloy sputtering target having a composition containing Sb and Te as main constituent elements thereof and carbon or boron in an amount of more than 10 at % and equal to or less than 30 at %, having a relative density of 97.85% or more, and having an average deflective strength of 100 MPa or higher, wherein the Sb—Te-based alloy sputtering target has a uniform structure comprising grains of an Sb—Te-based alloy phase and a uniform dispersion of grains of the carbon or boron, the grains of the Sb—Te-based alloy phase have an average size of 3 μm or less and a standard deviation of less than 1.00, the grains of the carbon or boron have an average size of 0.5 μm or less and a standard deviation of less than 0.20, and, for the average size of the grains of the Sb—Te-based alloy phase expressed by X and the average size of the grains of the carbon or boron expressed by Y, a ratio Y/X is within a range of from 0.213 to 0.5.