To provide a vacuum pump for priming a fire pump, capable of operation without the breakage of a blade even in the case of the appearance of liquid mixed with the intake air, and further capable of satisfying even a type approval test performed by Japan Firefighting Certification Institute.

A casing 10, covers 13 and 14 for closing both ends thereof, and a rotor 15 rotating at an eccentric position within the casing 10 are formed out of bronze casting, similar to the conventional case. Besides, a plurality of blades 19 slidable in the bearing grooves of the rotor 15 along entering and exiting directions are formed out of polyether, ether and ketone resin (PEEK) containing a lubricant and carbon fiber. Furthermore, a compressed liquid releasing hole is formed on the easing 10 at a position before an exhaust port 12, viewed from the rotating direction of the rotor 15, in common to a heat releasing hole.