To easily set the intensity distribution of emitted luminous flux with simple constitution by providing 1st and 2nd light source parts emitting 1st luminous flux whose cross section is zonal shape and 2nd luminous flux whose cross section is zonal shape or circular and a synthesis part synthesizing the 1st luminous flux and the 2nd luminous flux.

The 1st and the 2nd light source parts 11 and 12 are arranged so that the optical axes AX1 and AX2 of reflectors 15 and 16 may be orthogonally crossed. The luminous flux L1 from the 1st light source part 11 is all reflected by the reflection mirror 10a of the synthesis part 10, and the luminous flux L2 from the 2nd light source part 12 all passes through the aperture 10b of the synthesis part 10. Thus, the luminous flux L1 from the 1st light source part 11 and the luminous flux L2 from the 2nd light source part 12 are coaxially synthesized. By setting the inside diameter d1 of the luminous flux L1 and the outside diameter D2 of the luminous flux L2 to 30 mm, the minor axis of the elliptical aperture 10b to 30 mm and the major axis thereof to 42.4 (30×√2) mm, the luminous flux L1 and the luminous flux L2 come in contact with each other in the synthesized luminous flux L0, and the cross section of the luminous flux L0 becomes the zonal shape having the outside diameter D1 of the luminous flux L1 and the inside diameter d2 of the luminous flux L2.