The Mn-Zn ferrite ceramics with high density above 99.8% and fine grain size below 5 μm have been obtained by sintering of hydrothermal-precipitated ferrite powders at lower temperature than that in the ordinary process. Mn-Zn ferrite ceramics with grain sizes below 3μm have relative permeabilities comparable to that of commercial one in a frequency range above 5MHz. The single side MIG heads composed of ferrite with fine grain(Gs=2.3μm) are manufactured. The output voltage of the heads composed of the developed ferrite are equal to those of the heads composed of the commercial ferrite. The asymmetry instabilities of the heads composed of the developed ferrite are almost equal to those composed of the single crystal Mn-Zn ferrite which seemed to be good for the asymmetry instabilities. Therefore, Mn-Zn ferrite with fine grain sizes and high density is expected to be useful as magnetic head material for high density recording.