PURPOSE: To easily produce a high-density sintered body by sticking fine powder having the same compsn. as the compsn. of raw material powder forming a green compact to the surface of the compact and subjecting the compact to presintering in a nonoxidizing atmosphere, then to a hot isostatic press treatment.

CONSTITUTION: For example, Fe-Si alloy powder 4 having ≤44μ grain size is compacted under 2t/cm2 pressure to produce the columnar compact 1 sized 10×10mm. This compact 1 is immersed into ethyl alcohol dispersed with fine Fe-Si alloy powder 5 having ≤16μ grain size and is dried so that the fine powder 5 is stuck to the surface. This compact is presintered for one hour at 1400°C in a vacuum or inert atmosphere to substantially eliminate the open pores of the compact. This compact is further sintered by hot isostatic press treatment for one hour at 1400°C and under 2000atm. The high-density sintered body is obtd. by this method with the hot isostatic press which eliminates the labor for glass coating.