A shadow-free lamp assembly comprises a plurality of plane mirror segments disposed on a basic paraboloidal reflecting surface, and a linear light source. Each of the plane mirror segments has a length of the short span of the paraboloidal reflecting surface as its long side and is continuously disposed next to each other along the long span of the paraboloidal reflecting surface and the light source is disposed in reflecting direction forward from the focus of the paraboloidal reflecting surface, whereby all mirror segments reflect light from the light source to produce irradiation patterns illuminating the single illumination area. Because of the overlapped illumination by the plurality of the mirror segments, shadow is not produced on the illumination area when reflected light is partially intercepted.