A turbomolecular pump (10) comprises a stator (12, 18), a pump rotor (20) a motor (28) for driving the pump rotor and a control device (42). The control device (42) controls the motor output power such that the motor output power does not exceed a permissible maximum motor output power. On the stator side of the turbomolecular pump (10), temperature sensors (32 38) for measuring the stator temperature are arranged. The control device (42) comprises a maximum output power detecting device (50) that determines the permissible maximum motor output power in dependence on the measured stator temperature. Thus, the permissible maximum motor output power is not set to a constant value but always fixed in dependence on the current, measured stator temperature. Thereby, the capacity of the motor can be fully utilized as long as the measured stator temperature lies below a maximum value.