Provision of a reflective mask blank for EUV lithography having an absorber layer which has a low reflectance in the wavelength regions of EUV light and pattern inspection light and whose film composition and film thickness are easily controllable to desired ones.A reflective mask blank for EUV lithography, which comprises a substrate, and a reflective layer to reflect EUV light and an absorber layer to absorb EUV light, formed in this order on the substrate, wherein the absorber layer contains tantalum (Ta), boron (B) and silicon (Si), and in the absorber layer, the content of B is at least 1 at. % and less than 5 at. % and the content of Si is from 1 to 25 at. %, and wherein the absorber layer contains no nitrogen (N) or at most 10 at. % of N.