To provide a roots pump capable of suppressing the temperature rise of a rotor and a rotating shaft on an exhaust side.

A roots pump includes a low pressure side roots pump 10L, a high pressure side roots pump 10H, and a connection channel 41. The low pressure side roots pump 10L has a casing having one or more pump chambers 16a-16c; a pair of rotating shafts 21 rotating while supported by the casing; and rotors 22a-22c disposed in the pump chambers 16a-16c, and supported by the rotating shafts 21. The high pressure side roots pump 10H has a casing having one or more pump chambers 16a-16c; a pair of rotating shafts 21 rotating while supported by the casing; and rotors 22a-22c disposed in the pump chambers and supported by the rotating shafts 21. The connection channel 41 connects an exhaust hole 33 of the pump chamber 16c on the most downstream side of the low pressure side roots pump 10L and an intake hole 31 of the pump chamber 16a on the most upstream side of the high pressure side roots pump 10H.