There is provided a medical device whose occupied space is reduced. According to an aspect of the present invention, a medical device (1) adjusts a position of a medical instrument including a rod-like insertion unit (201) for being inserted into a body. The medical device includes an ultrasonic actuator that holds the insertion unit of the medical instrument, and that displaces or rotates the insertion unit with respect to the ultrasonic actuator, and an actuator fixing unit (101 and 102) that fixes a position of the ultrasonic actuator to a surgical site.
