PURPOSE: To obtain a ceramic fireproof protective sheet capable of imparting high fireproof performance only by sticking by producing prepreg using a matrix compsn. having a specified compsn. and carrying out heating and pressing under prescribed conditions after laminating.

CONSTITUTION: A matrix compsn. contg. fine metal oxide powder (A) of ≤1μm average particle diameter such as fine alumina powder, a soluble siloxane polymer (B) having a double-chain structure such as polysilsesquioxane, a terfunctional silane compd. (C) having an ethylenically unsatd. double bond such as γ-methacryloxypropyl-trimethoxysilane, an org. peroxide (D) and a radical-polymerizable monomer (E) having at least two ethylenically unsatd. double bonds in one molecule such as ethylene glycol diacrylate is prepd. A liq. contg. the compsn. or a sheetlike material of the compsn. is impregnated into a product or tow of inorg. fibers, laminated in a sheet shape, heated and pressed under the conditions of 120-250°C and 2-10kg/cm2 pressure to obtain the objective fireproof protective sheet.