PROBLEM TO BE SOLVED: To provide an ultrasonic probe support device which includes a rotation mechanism capable of smoothly rotating without being influenced by muscle in the case in which a long axis cross section of a blood vessel is shown in an ultrasonogram by rotating an ultrasonic probe 90 degrees from a short axis cross section of the blood vessel in vascular endothelium function test using an ultrasonic diagnostic device.SOLUTION: An ultrasonic probe support device 20 comprises: an ultrasonic probe holding section 23; and an ultrasonic probe rotation section 24 which supports the rotation of the ultrasonic probe holding section 23 in a state where an ultrasonic probe 11 is attached thereto. The ultrasonic probe rotation section 24 is attached to the position deviated from the center of the side surface of the ultrasonic probe holding section 23. The ultrasonic probe holding section 23 rotates with the center line of the ultrasonic probe rotation section 24 as a rotation axis.
