PURPOSE: To obtain a luminous unit capable of adjusting the levels of lamplight in optional colors using fluorescent lamps by receiving a light level adjuster which adjusts the levels of output light from the specific three fluorescent lamps in a casing main- body and providing the casing main-body with a window section in a specific mode in front of the fluorescent lamps.

CONSTITUTION: Three fluorescent lamps 11 provided thereabout with red (R), green(G) and blue(B) color filters are set side by side in a casing main-body 13. Also a light level adjuster 12 which independently adjusts the level of output light from each of the three fluorescent lamps 11 is received in the casing main-body 13. Moreover, the casing main-body 13 is provided with a light level adjuster cover 15 having a milky window section 15a wherethrough lamplight is transmitted in front of the three fluorescent lamps 11 and having its part other than the window section 15a screened from lamplight. Also the window section 15a of the light level adjuster cover 15 is formed in such a manner that a distance between the window section 15a and the fluorescent lamps 11 may be set to not less than a space between the two fluorescent lamps 11 set on both end sides and the width of the window section 15a may be set to not more than half the space, so that the level-adjusted output light of the three fluorescent lamps 11 can be smoothly mixed with one another.