Abstract: Provided is a vacuum pump which can detect precisely physical contact between a rotor portion and a stator portion, and contact between the rotor portion and the stator portion that occurs as the amount of deposited solid product reaches the clearance between the rotor portion and the stator portion. A vibration sensor is provided, taking advantage of a clearance, at the outer peripheral of a thread groove spacer. Contact between the rotor portion and the stator portion is decided, when a particular vibration during contact between the rotor portion and the stator portion exceeds a predetermined threshold value. The vibration sensor is mounted on the outer peripheral of the thread groove spacer at the end of the side of an exhaust port. The thread groove spacer is fixed on a casing via an elastic member (an O-ring) that have a vibration absorption (vibration damping) function of a cutoff frequency (fc1).