A housing for an electronic tuner or the like comprises: a shield frame defining a space to house circuitry, and an auxiliary base plate enclosing one side of the space left open by the frame and preferably serving to shield the circuitry in cooperation with the shield frame. A novel structure is disclosed for mechanically securing the auxiliary base plate to the shield frame simply and in such a manner that the auxiliary base plate can be easily removed if necessary. The frame and the auxiliary base plate engage each other elastically and resiliently by means of tongues, apertures and/or notches. No special step of either soldering or bending the auxiliary base plate or shield frame with pliers, etc., is required to maintain the parts in position. One or more shield plates may be supported by the auxiliary base plate and the shield frame and divide the space into sections.