A movable contact unit for a panel switch having (a) a substrate sheet of an insulating material having an electrically conductive layer on an entire upper surface, and provided with a opening at a predetermined position, (b) a dome-like movable contact of a thin resilient sheet metal placed in the opening of the substrate sheet, and (c) a dustproof sheet of an insulation film having flexibility, coated with an adhesive material on its underside, positioned over the opening of the substrate sheet, and adhesively conjoining the substrate sheet around a periphery of the opening and an upper part of the dome-like movable contact with the adhesive material. Also, a panel switch constructed of the movable contact unit placed and adhered on a substrate circuit board having stationary contact on its upper surface in a position such that the dome-like movable contact corresponds to the stationary contact.