A molecular pump has a cylindrical casing, a stator portion formed in the casing, a shaft disposed in the stator portion, a bearing pivotally supporting the shaft with respect to the stator portion, a rotor that is attached to the shaft and rotates integrally with the shaft, a motor for rotationally driving the shaft, a shock absorbing member, and a flange portion provided at an end portion of the casing. The flange portion has a bolt hole through which extends a bolt for fixing the casing and a fixed member to each other and an insertion hole which is provided adjacent to the bolt hole and in which the shock absorbing member is inserted so that at least one end side of the shock absorbing member extending along an axial direction of the bolt is spaced apart from the bolt.