A sintered hard alloy base material for surface-coated gear cutting tool that is for use as a base material of surface-coated gear cutting tool composed of a base material and, superimposed on a surface thereof, a hard coating layer. The sintered hard alloy base material is comprised of a WC-betat-Co alloy wherein the content of Co constituting the bonding phase of the base material is in the range of 12 to 17 wt.% and the content of components excluding WC of betat solid solution constituting the hard phase of the base material is in the range of 15 to 20 wt.% and wherein the total content of Ta and Nb carbonitrides is in the range of 5 to 8 wt.%.