A dimmer switch includes a main body and an operation portion. The operation portion is provided in the main body to be rotatable around a rotation axis to switch the dimmer switch among an off position, a low beam position, and a high beam position. The low beam position and the high beam position are provided above a horizontal line passing through the rotation axis and the off position is provided below the horizontal line in a state where the dimmer switch is attached to a vehicle body. A first rotation angle between the off position and the low beam position is set to be larger than a second rotation angle between the low beam position and the high beam position.