This invention relates to a TiAl intermetallic compound-based alloy exhibiting excellent heat resistance, oxidation resistance and resonance resistance and having a cast structure composed of fine equiaxed grains. Specifically, it relates to a TiAl intermetallic compound-based alloy comprising of 45 to 48 atomic percent of Al, 5 to 9 atomic percent of Nb, 1 to 2 atomic percent of Cr, 0.2 to 0.5 atomic percent of Si, 0.3 to 2 atomic percent of Ni, 0.01 to 0.05 atomic percent of Y, and the balance being Ti and incidental impurities, the alloy exhibiting excellent heat resistance, oxidation resistance and resonance resistance and having a cast structure formed of fine equiaxed grains.