Abstract: A rotator has an inner cylinder with a circular inner circumference surface, which is stored within a handy-type outer cylinder and rotatably driven by a motor, and a probe holder that is detachably inserted into the inner cylinder and which holds an ultrasound probe for providing two-dimensional image signals of body portions to be diagnosed by means of transmitting ultrasound beams in a stationary state. This probe holder has a cylindrical holder main unit arranged such that a cable extending from the rear end of the ultrasound probe is stored from the side of the holder, and a main unit fixing portion for fixing the holder main unit inserted into the inner cylinder to the inner cylinder, by pressing forwards.