PURPOSE: To obtain a hardenable inorganic composition excellent in incombustibility, appearance and strength and suitable as a raw material for an inorganic hardened body having excellent durability by blending an SiO2-Al2O3 based amorphous powder and an alkali metal silicate aq. solution with a specific inorganic filler.

CONSTITUTION: This hardenable inorganic composition is composed of 100 pts.wt. blended material made by blending the SiO2-Al2O3 based amorphous powder with the alkali metal silicate aq. solution in the blended ratio of 2:1 to 1:5 by wt. and 60-300 pts.wt. inorganic filler. This inorganic filler is composed of 10-86% filler having 50-300μm particle size, and 86-10wt.% filler having 0.01-25μm particle size and is 60wt.% in sum of the filler having these particle size. An inorganic hardened body excellent in incombustibility, appearance and strength, free from the generation of crack due to the shrinkage by hardening and breaking when tested by a freezing and thawing method and excellent in durability is produced by further adding 0.5-10 pts.wt. reinforcing fiber to this hardenable inorganic composition.