PURPOSE: To obtain an inorganic cured matter having no occurrence of efflorescence, and effect hydration quickly and also hasten the strength performance because a molding is held in a state of high humidity and thus subjected to moisture curing by sealing a hydraulic inorganic molding with a resin film and curing it thereafter.

CONSTITUTION: A resin film 13 is inserted between a receiving plate 14 provided on a conveyer 15 and a hydraulic inorganic molding 12 being extruded from an extruder 11, and both the ends thereof are superimposed each other and sealed to be cured thereafter. The curing is ordinarily performed in a sealed curing room at a low temperature of 60-80°C for almost 6-24 hours. In this instance, moisture evaporated from the surface of the inner part molding 12 sealed by the resin film 13 is saturated and, when it comes to be an equalized state with the saturated vapor pressure according to a curing temperature, moisture evaporation from the inner part of the molding 12 is restrained and thereby the occurrence of efflorescence is prevented perfectly.