This electromagnetic radiation detector consists of a plurality of elementary detection micro-sites, each including a micro-detector provided with a membrane (2) that is sensitive to the radiation in question and each being provided in a micro-cavity or micro-capsule defined by a substrate (1), by an upper wall (5) used as a window that is transparent to said radiation and by side walls (4), said membrane (2) being suspended above substrate (1) by means of at least two support arms (6) that include an electrically conducting layer (17), with the ends of said arms (6) being anchored in side walls (4).