The electromagnetic radiation detector compromises at least one radiation absorption membrane transforming the absorbed energy into heat transmitted to at least one resistive thermometer having a resistance varying with temperature. Each absorption membrane is suspended above a substrate by a nanowire connected to the central area of the membrane. The nanowire comprises an electrically conducting core and an electrically conducting external layer electrically insulated from one another and respectively connected to measuring areas of said thermometer. The nanowire serves the purpose both of support for the membrane and of electrical connection between the measuring areas and a circuit arranged at the level of the substrate.