A main body of a multi-stage Roots pump 11 is incorporated in a cover 47. A connecting flange 39, a muffler 40, a guide pipe 41 and a discharge pipe 42 constitute a discharge piping mechanism 64. The discharge pipe 42 incorporates a bellows 421. A connecting flange 58 and a suction pipe 59 constitute a suction piping mechanism 65. The suction pipe 59 incorporates a bellows 591. The bellows 421, 591 are incorporated in the cover 47.

Thus, loads generated when the bellows constituting part of the gas flow path of a vacuum pump are elastically deformed, by virtue of changes in internal pressures, are prevented from extending to auxiliary equipment.