Abstract: A device for measuring dynamic balance of a rotor including a shaft to which an impeller is secured at its one end and which has a neck portion adjacent to the impeller so that the shaft may be rotatably supported by a bearing member at the neck portion. The device comprises: a housing member, a thrust bearing secured to the housing member and engageable with the neck portion of the shaft, a support member provided in the housing member beneath the thrust bearing and engageable with the shaft so that the shaft may be rotatably supported in a slanted or a vertical position by the support member and the thrust bearing with the impeller being positioned upward, and a sensor connected to the housing member for detecting the vibration of the housing member caused when the rotor supported by the thrust bearing and the support member is rotated. The dynamic balance of the rotor can be measured by the sensor in terms of the vibration of the housing.