Abstract: A collimator for a scintillator, having a number of through holes formed side by side, each for guiding and passing radiation from one end thereof to an other end and focusing the radiation at a predetermined position, including a frame made of a radiation shielding material, and defining a radiation transparent field of view, and a septa section provided in a lattice form in the field of view so as to define the through holes. The septa section includes a plurality of first partition plates arranged at substantially equal intervals and a plurality of second partition plates crossing the first partition plates in a lattice form. The first and second partition plates are made of a material, preferably tungsten or lead alloy, that sheilds the radiation. A plurality of focused slits are formed in at least either the first or second partition plates with the other partition plates being fitted in the slits.