Rotary operating device

A rotary operating device comprising:

• a case having a cavity, the cavity having an annular shape with an opening at a top;
• a rotating shaft member having an annular shape, rotatable with respect to the case, and closing the cavity;
• an operation member having an annular shape with an opening at a bottom, covering the cavity, engaging with the rotating shaft member, and rotating together with the rotating shaft member;
• and
• a sensor disposed within the cavity to detect rotation of the rotating shaft member,
• wherein the case has an inner peripheral wall having an annular shape,
• wherein the operation member has an inner cylindrical portion having an annular shape,
• wherein the rotating shaft member has a peripheral wall that extends downward and extends along an outer peripheral surface of the inner peripheral wall, and
• wherein a first gap between the inner peripheral wall of the case and the peripheral wall of the rotating shaft member is smaller than a second gap between an inner peripheral surface of the rotating shaft member and the inner cylindrical portion of the operation member.