A switch device includes a box-shaped case, a harness portion, and a fixing member. The harness portion is connected to a switch contact point and includes a plurality of lead lines extending out of the case. The case includes a holding body and a guide portion. The holding body includes a fixing portion protruding from an outer face of the case and provided on a tip side, and a through-hole provided under the fixing portion. The guide portion is opposed to the through-hole and formed in a substantially concave curve shape. The guide portion is formed such that an end portion further from the through-hole is positioned to be above an end portion closer to the through-hole. The fixing member extends through the through-hole and fixes the harness portion to the holding body by winding the harness portion and the fixing portion together.