An operation knob device includes an annular holder having an annular holding portion, an annular rotor arranged in the holding portion so as to allow rotation around an axis, an annular knob for which relative movement in a direction along the axis with respect to the rotor is allowed and relative movement in a circumferential direction around the axis is restricted, a first transmission member arranged on a side of a first end of the rotor so as to move with the knob, and a second transmission member attached to the first end so as to rotate integrally with the rotor. The knob has cylindrical inner and outer wall portions, and an opening through which part of a display panel can be visually recognized is defined by the inner wall portion. The first and second transmission members are arranged between the inner wall portion and the outer wall portion.