A switch device in which: a band-shaped movable piece is supported in a position of being separated from an opposing face of a polar board to the movable piece by a support portion of the polar board for supporting a midway position of the movable piece in the longitudinal direction, the movable piece being provided to be capable of swinging in a direction where one side and the other side of the movable piece in the longitudinal direction are connected to or disconnected from a first fixed contact point and a second fixed contact point formed to be projected toward the movable piece from the opposing face of the polar board; and a movable board provided with an urging member for urging the movable piece to the polar board is provided to be capable of moving forward/backward in the longitudinal direction in association with an operation of a knob, wherein when the movable board moves to the one side in the longitudinal direction, the urging position of the movable piece by the urging member is displaced to the one side in the longitudinal direction to cause the one side of the movable piece in the longitudinal direction to make contact with the first fixed contact point, and when the movable board moves to the other side in the longitudinal direction, the urging position of the movable piece by the urging member is displaced to the other side in the longitudinal direction to cause the one side of the movable piece in the longitudinal direction to be disconnected from the first fixed contact point, characterized in that a restriction member is provided between the support portion of the polar board and the first fixed contact point to restrict the movement of the movable piece to the polar board, a height of the restriction member from the polar board being set to a height in such a manner as to abut on the movable piece in a point where a height of the first fixed contact point from the polar board reaches a predetermined height due to wear, and in the support portion, the movable piece is supported to be displaceable in the longitudinal direction of the movable piece, wherein when the one side of the movable piece makes contact with the first fixed contact point, in a case where the restriction member makes contact with the movable piece, the movable piece is displaced in the longitudinal direction on a basis of the contact position with the restriction member to be disconnected from the first fixed contact point. a band-shaped movable piece is supported in a position of being separated from an opposing face of a polar board to the movable piece by a support portion of the polar board for supporting a midway position of the movable piece in the longitudinal direction, the movable piece being provided to be capable of swinging in a direction where one side and the other side of the movable piece in the longitudinal direction are connected to or disconnected from a first fixed contact point and a second fixed contact point formed to be projected toward the movable piece from the opposing face of the polar board; and a movable board provided with an urging member for urging the movable piece to the polar board is provided to be capable of moving forward/backward in the longitudinal direction in association with an operation of a knob, wherein when the movable board moves to the one side in the longitudinal direction, the urging position of the movable piece by the urging member is displaced to the one side in the longitudinal direction to cause the one side of the movable piece in the longitudinal direction to make contact with the first fixed contact point, and when the movable board moves to the other side in the longitudinal direction, the urging position of the movable piece by the urging member is displaced to the other side in the longitudinal direction to cause the one side of the movable piece in the longitudinal direction to be disconnected from the first fixed contact point, characterized in that a restriction member is provided between the support portion of the polar board and the first fixed contact point to restrict the movement of the movable piece to the polar board, a height of the restriction member from the polar board being set to a height in such a manner as to abut on the movable piece in a point where a height of the first fixed contact point from the polar board reaches a predetermined height due to wear, and in the support portion, the movable piece is supported to be displaceable in the longitudinal direction of the movable piece, wherein when the one side of the movable piece makes contact with the first fixed contact point, in a case where the restriction member makes contact with the movable piece, the movable piece is displaced in the longitudinal direction on a basis of the contact position with the restriction member to be disconnected from the first fixed contact point.