PURPOSE: To obtain a hydraulic material not causing efflorescence, forming surface gloss by polishing, etc., and excellent in salinity tolerance by curing a mixture of the hydraulic material and a specified material.

CONSTITUTION: A mixture of a hydraulic material (e.g. portland cement) and one or more kinds selected from a gelatin soln. hot-dissolved by adding water, a glue soln. hot-dissolved by adding water, a collagen soln., milk or its soln., defatted milk or its soln., a casein soln., albumin or its soln., soybean milk or its soln., a starch soln. hot-dissolved by adding water, a starch sugar soln., a devil's-tongue soln., a cellulose soln., a nitrocellulose soln., a viscose soln., a silk fibroin soln., an agar soln. hot-dissolved by adding water, a gelidium jelly soln., a glue plant soln., hot-dissolved by adding water, a pearl essence and a fine mica powder is cured.