Abstract: A operation knob device (10) for an armrest, that is configured to unlock the armrest and moves the armrest to a useable state, includes: a knob min body (30) having an operation knob (32); and an inner case (50) disposed around the knob main body (30) and configured to expose the operation knob (32) from a first opening (55). The inner case (50) includes a plurality of case protrusions (60) that protrude from a lower region (54a) of a lower edge of the first opening (55) toward the knob main body (30). The knob main body (30) includes a plurality of main body protrusions (40) that protrude toward the lower region (54a) of the inner case (50). The plurality of case protrusions (60) and the plurality of main body protrusions (40) are alternately disposed when viewed in a +Z direction.

Abstract: A operation knob device (10) for an armrest, that is configured to unlock the armrest and moves the armrest to a useable state, includes: a knob min body (30) having an operation knob (32); and an inner case (50) disposed around the knob main body (30) and configured to expose the operation knob (32) from a first opening (55). The inner case (50) includes a plurality of case protrusions (60) that protrude from a lower region (54a) of a lower edge of the first opening (55) toward the knob main body (30). The knob main body (30) includes a plurality of main body protrusions (40) that protrude toward the lower region (54a) of the inner case (50). The plurality of case protrusions (60) and the plurality of main body protrusions (40) are alternately disposed when viewed in a +Z direction.