PURPOSE: To provide a manufacturing method for simple roof tiles capable of affording diversified designs, surface decorations, and large-sized formed items by enabling formation even in a small quantity of water.

CONSTITUTION: A hydraulic inorganic composite 2 is supplied into an extruder 1, and an uncured inorganic continuous formed body 4 is extruded by passing through a dies 3 mounted on the tip end of the extruder 1, and then the surface of the inorganic continuous extruded formed body 4 is cut in its side surface while giving decoration on the inorganic continuously extruded formed body 4 by means of a decoration roller 5 having irregular patterns on its surface and a cutting blade.