A wire holder includes a synthetic resin component that includes a clamp portion for holding at least one wire and a metal component that includes at least one lead portion mounted on a circuit board. The synthetic resin component includes a groove-shaped fitting groove portion. The metal component includes at least one fitting portion that fits the fitting groove portion and is connected to the lead portion. The fitting groove portion includes at least one first opening portion which allows the at least one lead portion to project in a predetermined direction when the at least one fitting portion fits the fitting groove portion. At least one of end portions in an extension direction of a groove of the fitting groove portion is opened as a second opening portion which allows one of the at least one lead portion to project along the extension direction of the groove of the fitting groove portion.