To manufacture a ceramic building material having an excellent strength by activating a reaction of a cement matrix in the case of recycling a dry scrap as an aggregate.

A method for manufacturing the ceramic building material comprises the steps of dipping the dry scrap in a cement blending material of the ceramic building material made of the aggregate containing a cement, a silica and the dry scrap, a reinforcing fiber and the like in an aqueous solution obtained by dissolving a colloidal silica for one minute to two hours before mixing in the case of mixing the blending material together with a necessary adding water, then mixing another material and necessary moisture, shaping the mixture, curing and hardening the mixture after shaping.