The present disclosure provides a vacuum pump of which a thermal resistance between a heater and a water-cooling tube is high and which has a small number of components. The vacuum pump includes: a main body casing having an intake portion and an exhaust portion of gas; a turbo-molecular pump mechanism portion in which stator blades and rotor blades are formed; and a motor for rotating the rotor blades, wherein the main body casing has a base spacer capable of thermal conduction between a heating spacer portion and a water-cooling spacer portion having been integrally molded, and the base spacer is provided with a boundary portion having been molded such that a cross section thereof assumes a narrow neck shape between the heating spacer portion and the water-cooling spacer portion.