PURPOSE: To enable the adequate increase in the density and porosity of formed articles by adjusting the liquid specific gravity and concn. of a principal forming agent and forming assistant to be mixed with a raw material for formed articles.

CONSTITUTION: The liquid specific gravity and concn. (Baume) of the 1st liquid (principal forming agent) and the 2nd liquid (forming assistant) to be mixed with a raw material for formed articles are beforehand set the same to prohibit the substitution of the 1st liquid in the formed articles with the 2nd liquid, then formed articles are made in a high density. Conversely, if the specific gravity and concn. of the 1st liquid and the 2nd liquid are changed, the substitution equal to the difference thereof is induced and the porous formed articles are obtd. If it is not possible to make a difference in the concn. and specific gravity between the 1st liquid and the 2nd liquid, these liquids are dipped in water of distilled water as the 3rd liquid to generate a difference in the liquid specific gravity, whereby the porous formed articles by each objects are produced.