A turbomolecular pump comprising a rotor and a stator housed in a casing and forming an exhaust channel therebetween, and a suction port and a discharge port formed in the casing; wherein the turbomolecular pump has a valve body for opening and closing the suction port, the valve body is movable in an axial direction of the turbomolecular pump, a valve driving mechanism for driving the valve body via a valve body supporting member which extends through a throughhole formed in the rotor and/or the stator and magnetic bearing units for non-contactingly supporting the valve body supporting member within the throughhole, whereby a turbomolecular pump having a compact overall construction including valve units can be provided.