Switch device

A switch device comprising:

• a switch;
• a casing accommodating the switch;
• a pair of side wall portions extending in a first direction from the casing;
• a front wall portion extending in the first direction from the casing;
• a back wall portion extending in the first direction from the casing;
• a dust-proof portion extending from the back wall portion;
• and
• an operation knob including
• an upper surface portion which is mounted on the casing so as to be swingable in a second direction perpendicular to the first direction and a third direction opposite to the second direction and covers the dust-proof portion along the first direction, and
• a back surface portion which extends in a fourth direction opposite to the first direction from the back end of the upper surface portion and faces at least a part of the dust-proof portion,
• wherein, in a plan view observed in the first direction, the side wall portions, the front wall portion, and the back wall portion form a substantially rectangular shape,
• wherein the side wall portions, the front wall portion, and the dust-proof portion form a substantially rectangular shape, and
• wherein the substantially rectangular shape formed by the side wall portions, the front wall portion, and the dust-proof portion is greater than the substantially rectangular shape formed by the side wall portions, the front wall portion, and the back wall portion.