To improve a low long-term strength development which has been a problem of no-called ecocement (economical cement) by adding a slag of a specific composition, to effectively use a waste on the whole and to make it into resources since a waste liquid slug can be used as a slag composition.

This hydraulic composition comprises (A) a baked material which is obtained from incinerated ash of waste as a raw material and is composed of 0-40 wt.% of one or more selected from C11A7CaCl2, C11A7CaF2 and C3A and C2S and/or C3S, (B) an amorphous slag composition composed of 0-37 wt.% of CaO, 23-90 wt.% of SiO, 0-40 wt.% of Al2O3 and 0.1-50 wt.% of one or more selected from Fe2O3, Na2O, K2O, P2O5, TiO2, MnO and MgO and/or 0.01-10 wt.% of a halogen and having 2,000-15,000 cm2/g Blaine method and (C) gypsum.