PURPOSE: To prevent illuminance reduction at the limited height by providing rotary paraboloid reflecting mirrors having a focal point at a light source on the upper rear, lower right and lower left of the light source, radiating parallel light forward directly from the former, and radiating parallel light forward via two plane mirrors on both wings respectively from the latter.

CONSTITUTION: A reflecting mirror 2 made of nearly the upper half section of a rotary paraboloid having a focal point nearly at a light source 1 is formed behind the filament 1a of the light source 1, reflecting mirrors 3, 4 made of rotary paraboloids having the focal point nearly at the position of the light source 1 are formed on the lower right and left, and the light of the light source 1 is made parallel light and is divided horizontally on the right and left. The light is reflected upward by plane mirrors 5, 6 and forward by plane mirrors 7, 8 and is projected forward through an integrated lens together with the light from the reflecting mirror 2. Even a luminaire limited in height to the utmost can increase the light beam utilization factor, obtain the prescribed brightness without increasing power consumption, and easily optimize the horizontal and vertical light distribution characteristics via the adjustment of the plane mirrors 5, 6, 7 and 8.