Provided is a wiring thin plate capable of suppressing deterioration of an electric characteristic and variation in thickness of an aerial wiring portion while advancing reduction of rigidity of the aerial wiring portion. The wiring thin plate includes an aerial wiring portion including wiring traces and passing over an airspace, aerial base layers provided at the respective wiring traces in the aerial wiring portion and being apart from each other, and an aerial cover layer provided in the aerial wiring portion and spanning from the wiring traces of the aerial wiring portion through the aerial base layers to interspaces between adjacent aerial base layers of said aerial base layers.