Provided is a sintered silicon wafer, wherein the volume ratio of silicon oxide contained in the wafer is 0.01% or more and 0.2% or less, the volume ratio of silicon carbide is 0.01% or more and 0.15% or less, and the volume ratio of metal silicide is 0.006% or less. Additionally provided is a sintered silicon wafer having a diameter of 400 mm or more and having the following mechanical properties (1) to (3) measured by collecting a plurality of test samples from the sintered silicon wafers: (1) average value of the deflecting strength based on a three-point bending test is 20 kgf/mm2 or more and 50 kgf/mm2 or less; (2) average value of the tensile strength is 5 kgf/mm2 or more and 20 kgf/mm2 or less; and (3) average value of the Vickers hardness is Hv 800 or more and Hv 1200 or less. Even in the case of a large disk-shaped sintered silicon wafer, it is possible to provide a sintered compact wafer having definite strength and similar mechanical properties as single crystal silicon.