PURPOSE: To form a uniform SOI layer on an entire substrate with excellent controllability by selectively epitaxially growing a silicon layer on the exposed part of a first silicon substrate, and polishing the substrate with a first insulating film as a stopper from the opposite side surface of a second silicon substrate to the bonding surface of the second substrate.

CONSTITUTION: A silicon oxide film is deposited on a first silicon substrate 1, formed as a first insulating film 2, and the film 2 is partly removed to expose the substrate 1. Then, a silicon layer 3 is epitaxially grown on the exposed part of the substrate 1, a silicon oxide film is deposited thereon as a second insulting film 4, and the surface is then flattened. Thereafter, a second silicon substrate 6 formed with an insulating film 5 on the surface is prepared, and the films 4 and 5 are adhered. Then, the substrate 1 is polished from the opposite side surface to its bonding surface with the film 2 as a stopper to be removed thereby to expose the layer 3, thereby obtaining a thin film SOI substrate. Thus, the controllability of the thickness of the film 3 is high and the layer 3 can be fanned uniformly on the entire substrate.