Abstract: A turbo molecular pump comprising a plurality of moving blades and stationary blades arranged alternately in the axial direction in a pump casing having a gas suction port and exhaust port, a thread groove pump stage disposed on the exhaust side of the moving and stationary blades, and a spacer for fixing the position intervals of the stationary blades, characterized in that a heating apparatus includes a radiating plate is provided in a gas passage of the thread groove pump stage, and the radiating plate is connected to a heating portion located on the outside of the pump by a good heat conductor. The heating apparatus heats the gas in the thread groove pump stage to a temperature above the gas sublimation temperature.