A ferrite powder for producing a ferrite sintered body is provided, the ferrite powder having a median diameter D50 [μm] in a range from 0.1 to 0.8 μm, a degree of spinel formation in a range from 45 to 90%, and a remanent magnetization Br per unit mass [emu/g] satisfying the following formula after application of the maximum magnetic field of 15 kOe: 0.05≦Br≦2.0(ln.D50)+6.3. This ferrite powder produces a homogeneous ferrite sintered body having very few cracks by gel casting.