A cordierite sintered body and a member for semiconductor manufacturing apparatus are disclosed. The cordierite sintered body includes a crystal phase and an amorphous phase. The crystal phase includes a main crystal phase that essentially consists of cordierite crystal grains; and a sub crystal phase that includes sub crystal grains containing alumina, mullite or sapphirine. The amorphous phase contains calcium and is located at grain boundaries of the cordierite crystal grains and the sub crystal grains. A crystal phase proportion of the main crystal phase to the crystal phase (or total of the main crystal phase and the sub crystal phase) is 95% to 97.5% by mass or less. A crystal phase proportion of the sub crystal phase to the crystal phase is 2.5% to 5% by mass or less. The sintered body contains calcium by 0.4% to 0.6% by mass or less in terms of CaO.