To provide carbonation curing equipment which can maintain the concentration of carbon dioxide gas to an optional concentration exceeding 20%, preferably, to an optional concentration exceeding 30%.

The carbonation curing equipment has a shielded space storing a cement hardened body and shielding the same from the external atmospheric environment, the shielded space has a gas introduction port connected to a carbon dioxide gas feed source via a gas flow rate regulation mechanism and a gas exhaust port connected to the outside via a gas inflow prevention mechanism, and the gas flow rate regulation mechanism and the gas inflow prevention mechanism can be subjected to a switching operation in such a manner that the control mode of the internal atmosphere is set to at least either a "gas replacement mode" or a "stationary mode". This equipment is particularly suitable to the carbonation curing for the hardened body of cement kneaded matter comprising low-heat portland cement and C2S, and in which the blending amount of C2S is 3010 pts.mass to 100 pts.mass of a binder, and the ratio of water to the binder is 35%.