A radio resource allocation method is provided wherein one of a plurality of mobile stations is allocated to one or each of a plurality of frequency blocks. The method comprises: (a) calculating allocation index representing transmission quality of each of said mobile stations in said each of frequency blocks; extracting for said each of frequency blocks, a mobile station having a largest allocation index as a candidate mobile station; (c) extracting a mobile station having a largest allocation index in all of said frequency blocks, as a target mobile station for allocation; and (d) extracting, from among said frequency blocks, frequency block(s) for which said candidate mobile station matches said target mobile station, as candidate frequency block(s).