An operating knob to be attached to a supporting member includes an operating part and a connector. The connector is attached to the operating part and includes a fitting cylindrical portion, a stopper disposed at an inner circumferential side of the fitting cylindrical portion to protrude on a radial inside, and housing portion. When the operating part is applied with a load greater than or equal to a predetermined value from an exterior in a direction toward the supporting member in a state where a fitting portion of the supporting member is fitted into the fitting cylindrical portion, the stopper is bent from the radial inside to a direction approximately parallel to the rotation axis so as to be housed in the housing portion and the fitting cylindrical portion moves toward the supporting member along an outer circumference of the fitting portion.