There are provided a reflective mask and a reflective mask blank reducing reflection of out-of-band light and a manufacturing method therefor. A light shielding frame is formed on a mask region corresponding to a multiply exposed boundary region between a chip and a semiconductor substrate. The frame is provided with an antireflective layer causing surface reflection in antiphase to out-of-band light reflected from the surfaces of a rear-surface conductive film and the substrate to provide a reflective mask reducing reflection of out-of-band light. The antireflective layer of the present disclosure has an electrical conductivity of 1×104/mΩ or greater to minimize charging occurring in a pattern region in observing the region using an electron microscope.