To provide a method capable of manufacturing in a short time and under low pressure carbonating environment and capable of obtaining an inorganic carbonated hardened body having excellent mechanical strength and excellent stability of the structure with time.

The method of manufacturing an inorganic carbonated hardened body comprises mixing a needle-shaped wollastonite simple substance that has 1.5-2.1 μm of 10% cumulation diameter, and 3.5-8.5 μm of 50% cumulation diameter, and 11.0-39.0 μm of 90% cumulation diameter in the grain size volume distribution or an inorganic material containing the wollastonite with water, shaping the mixture, and subjecting the shaped product to the carbonation treatment at 30°C-120°C.