PURPOSE: To adjust the upper face of a recessed lxminaire in the same level as a floor.

CONSTITUTION: An outer casing 21 is embedded in and fixed to a floor 15. An inner casing 35 is stored in the outer casing 21. The outer casing 21 and the inner casing 35 are connected together via plural level adjusting screws 17. With the rotation of the level adjusting screws 17, the inner casing 35 is moved up and down. The upper side of the inner casing 35 is covered with a cover 37 which has a surface plate 55 and a light transmitting portion 53a. As a result, even after a luminaire 11 is set up and a finishing material 14 for the floor 15 is applied, the height of the surface plate 55 can be easily adjusted and matched to the surface level of the floor 15.