To eliminate operation failure such as operation force and a click-stop sense due to mechanical contact of a notch device of a dial operating tool or need for another mechanism to reduce the operation force, and to facilitate assembling and maintenance, and to downsize it into a relatively small size.

The dial operating tool comprises an annular component 4 made of magnetic material and having a plurality of internal teeth projected to the inside of the radial direction at predetermined intervals on the inner circumference, a rotator 10 prepared rotatably around the center of the radial direction of the internal teeth of this annular component 4, and an operating knob 12 for rotating the rotator 10.