PURPOSE: To obtain an impregnated composite material having sufficient flexibility and sufficient rigidity, by pretreating a fibrous structure with a specific mixed treatment solution to improve it, impregnating it with a specific polyurethane composition.

CONSTITUTION: A fibrous structure such as a woven or knitted material consisting of natural or synthetic fiber is pretreated with a mixed solution of colloidal or synthetic fiber is pretreated with a mixed solution of colloidal silica and alumina zol, so that it is provided with 0.1W8wt% (solid content) of both the components, respectively. It is then impregnated with a W/O emulsion type polyurethane composition wherein water is dispersed into a solution of polyurethane in an organic solvent such as methyl ethyl ketone, etc., to give an impregnaged composite material having sufficient flexibility and rigidity useful as a simulated synthetic leather substitute.