PROBLEM TO BE SOLVED: To provide a magnetic oxide sintered compact which allows the materialization of a small-sized antenna usable over a wide band in RF band at a high efficiency and excellent in terms of productivity and economic efficiency, and the like, and to provide an antenna and a radio communication device, both using the magnetic oxide sintered compact.SOLUTION: The magnetic oxide sintered compact comprises, as its main phase, M-type hexagonal ferrite expressed by MA[FeMBMn]O, where MA is at least one element selected from the group consisting of Sr and Ba; MB is at least one element selected from the group consisting of Ti, Sn and Zr; and 1≤α<1.4; 7≤&bgr;≤11; 11.8≤&bgr;+(γ+δ)≤12.1; and 1≤δ/γ≤1.2. The average crystal grain diameter (long diameter) is 5 μm or larger.
