PURPOSE: To efficiently and easily manufacture a sintered powder compact by adding liquid compound having the specific characteristic of the specific quantity to sintering powder, compacting, exposing a part of the green compact, heating after coating the green compact with resin film and dispersing additive.

CONSTITUTION: To the sintering powder of ceramic or metal, the additive composed of the liquid compound of benzene, water, etc., having ≥-10°C m.p. and ≤140°C b.p. is mixed at 0.6-1.1 ratio per 1 of the above powder. The composition obtd. with this is pressed into a metallic mold and injection compacting is executed. Then, temp. of a cylinder is held to the m.p. or higher and lower than the b.p. of the above additive and temp. of the metallic mold is held to lower than the m.p. of additive. After that, the solidified powder green compact is taken out from the metallic mold and the resin film having air-tightness and elasticity is applied under remaining a part of exposed surface. Successively, the powder green compact is heated at the b.p. or higher of the additive under condition of isostatic-pressing to the coated surface to disperse the additive through the above exposed surface. By this method, the sintered powder compact without any detect of crack, etc., is efficiently obtd. and after that, successively heating the compact severely, ceramic sintered body, metal sintered body, etc., can be obtd.