There is provided a sheet-form molding which is outstanding in fire retardation and prevention of flame spread, exhibiting good fire retardant and flame spread-preventive effects based on its good form retention during combustion, and also outstanding in mechanical strength and stability, particularly with a reduced incidence of necking and shrinkage, thus insuring high dimensional accuracy in use and precision in application. Particularly, there is provided a sheet-form molding comprising a single layer or a plurality of layers, which has at least one layer consisting essentially of formulating 0.1 to 100 weight parts of a lamellar silicate, and 0.1 to 70 weight parts of a metal hydroxide and/or 0.1 to 50 weight parts of a melamine derivative in each 100 weight parts of a thermoplastic resin.