To improve a stopping looseness of a binding part, and further reduce a positioning work amount of a set screw.

This is an illumination fixture in which both screws are screwed and bound so that each other's matching faces are nearly adhered by installing a male screw 5 at one binding part 3 and by installing a female screw at the other binding part among a pair of binding parts respectively installed at the fixture main body and at an illumination part. A fitting groove 7 is installed at the one binding part 3 installed with the male screw 5 in nearly parallel against the matching face 6 along this circumferential direction, and the tip of the set screw penetrated into the inner side of the female screw is fitted to this fitting grove 7. By this, the stopping looseness of the binding part 3 can be improved greatly by inserting the set screw into the fitting grove 7. Further, the positioning work amount of the set screw can be made less because the set screw corresponds with the fitting groove 7 irrespective to the position around the shaft of the male screw 5.