A switch device, comprising: switches; a case in an interior of which the switches are accommodated; tube portions provided on an upper surface of the case, the tube portions opening in the up and down direction of the case and communicating with the interior of the case; a plurality of first operation knobs for opening/closing windows provided swingably in the front and back direction of the case so as to cover upper openings of the tube portions; operation rods passing through the openings of the tube portions from the first operation knobs and extending into the interior of the case, the operation rods being for transmitting movement of the first operation knobs to the switches; and a cover covering the upper surface of the case while exposing the first operation knobs, the first operation knobs being arranged so as to be spaced from each other in the front and back direction of the case, a first projection protruding towards the cover is provided on the upper surface of the case between the first operation knobs arranged in the front and back direction, a second projection protruding towards the case is provided on a back surface of the cover between the first operation knobs arranged in the front and back direction, the first projection and the second projection are arranged in a space between the cover and the case formed when the case is covered by the cover so as to overlap with each other when seen from the front and back direction, and characterised in that a groove portion extending in the left and right direction of the case so as to flow water to the sides of the case is provided between the back side of the first and second projections (15, 56) and the front side of the tube portion corresponding to the first operation knob among the first operation knobs arranged in the front and back directions on the back side of the first and second projections (15, 56). switches; a case in an interior of which the switches are accommodated; tube portions provided on an upper surface of the case, the tube portions opening in the up and down direction of the case and communicating with the interior of the case; a plurality of first operation knobs for opening/closing windows provided swingably in the front and back direction of the case so as to cover upper openings of the tube portions; operation rods passing through the openings of the tube portions from the first operation knobs and extending into the interior of the case, the operation rods being for transmitting movement of the first operation knobs to the switches; and a cover covering the upper surface of the case while exposing the first operation knobs, the first operation knobs being arranged so as to be spaced from each other in the front and back direction of the case, a first projection protruding towards the cover is provided on the upper surface of the case between the first operation knobs arranged in the front and back direction, a second projection protruding towards the case is provided on a back surface of the cover between the first operation knobs arranged in the front and back direction, the first projection and the second projection are arranged in a space between the cover and the case formed when the case is covered by the cover so as to overlap with each other when seen from the front and back direction, and characterised in that a groove portion extending in the left and right direction of the case so as to flow water to the sides of the case is provided between the back side of the first and second projections (15, 56) and the front side of the tube portion corresponding to the first operation knob among the first operation knobs arranged in the front and back directions on the back side of the first and second projections (15, 56).