To obtain an inexpensive dummy water which has a high strength, a high thermal shock resistance, etc., and can be used repeatedly and from which a film deposited on the wafer hardly comes off when the wafer is used for a film forming equipment.

A dummy wafer is formed on crystallized glass. Various kinds of crystallized glass having different compositions can be used for the dummy glass. In this example, such crystallized glass that has a bending strength of ≥8 kg/mm2 and a coefficient of thermal expansion of 1×10-7-150×10-7/°C is used. The crystallized glass can be transparent, translucent, or opaque and, when the glass is transparent or translucent, a light transmission preventing film, etc., is formed on the surface of the glass. In addition, such crystallized glass is coated with a hot-melt-spray-coating film to be used as the dummy wafer.