Abstract: A collimator obtained by the alternate stacking of metal sheets 1 (40 &mgr;m thick) having holes 4 with a width of 2200 &mgr;m in the center thereof, and metal sheets 2 (10 &mgr;m thick) devoid of holes (the metal sheets 1 with the holes 4 are shown in the state in which they exist before being cut in the manner described below, the metal sheets 1 in the upper portion of the figure and the metal sheets in the bottom portion are not connected with each other in the finished product). The opposite sides are held by metal pressing sheets 3 that are 2 mm thick. These metal sheets and pressing sheets are bonded by means of diffusion bonding based on thermocompression bonding. The portions with the vertical through-holes 4 (40 &mgr;m×2000 &mgr;m) thus become light-transmitting portions, the metal sheets 2 serve as partitions between adjacent holes 4, and light collimated to a width of 40 &mgr;m can ultimately pass through.