To provide a concrete form which is made of a waste plastic or a waste plastic mixed with waste wood and prevents harmful effect due to wasting by reusing the waste plastic and waste wood without necessity of wasting them after use and further substitutes for the South Sea timbers in uses for preventing cutting of tropical forest causing deterioration of global environment and is not rotten and recycled many times and has aesthetic appearance and strength.

The recovered waste plastic and waste wood are crushed and the mixture with a ratio corresponding to respective amounts of heat is fed to an extrusion molding machine, a press molding machine or an injection molding machine, and is melt, extruded and injected to form a predetermined shape (patterns are formed on a bonding surface of concrete) and is cured through cooling to produce a form. When the form is used and wasted after use, the form is crushed to a proper size after recovery and is recycled as a energy source having proper amount of heat.