A medical apparatus includes: a casing that forms an exterior, a single manipulation ring rotatably provided on an outer surface of the casing, and control circuitry. The control circuitry is configured to detect rotation of the single manipulation ring; calculate a rotation direction and a rotation angle of the single manipulation ring based on a detection result; execute a first function or a second function depending on the rotation direction and the rotation angle of the single manipulation ring calculated, wherein the first function is a different type of adjustment than the second function; and switch a function executed by the control circuitry to the first function or the second function.