PURPOSE: To easily adjust illumination in a cage or enable simple change and alteration of design, picture pattern, etc. on an illumination plate by providing a groove on a frame rod constituting an illumination frame on the underside of the illumination plate and constituting a douser fitted in the groove.

CONSTITUTION: A light source 2 is provided above a cage and an illumination frame 4 assembled into a lattice type is suspended beneath the light source. A transparent illumination plate 5 is mounted on the illumination plate 4 to be fixed by a fixture 6. The illumination frame 4 is provided on the side face of respective vertical and lateral frame rods 3, 3... with notch grooves 7 over the whole length into which dousers are inserted. Also, at least one spot in one division is subjected to facing to have a leaf spring 9 embedded therein for holding the douser 8. Thus the douser 8 is slid along the groove 7 in the frame rod 3, so that the illumination position of the illumination plate 5 can be varied. The leaf spring 9 presses the douser 8 against the groove 7 in the illumination frame 4 to fix the douser 8. Thus, the illumination of the cage can be easily varied by the movement of the douser 8.