PURPOSE: To obtain the subject nonwoven fabric, composed of a specifically arranged filament inorganic fiber layer and short inorganic fiber layer, excellent in heat resistance, mechanical strength, etc., and used for producing FRP reinforcing materials improved in dimensional stability, etc.

CONSTITUTION: The objective nonwoven fabric obtained by arranging at least one layer of fiber group obtained by opening a fiber assembly composed of plural filament inorganic fibers (e.g. glass fiber) oriented parallel in the longitudinal direction according to a chemical method, etc., and short inorganic fibers prepared by cutting the aforementioned filaments to 20-30mm length so as to provide at least one layer of the short inorganic fibers in the direction nearly perpendicular to the above-mentioned filaments (at preferably ≤0.7 ratio of the longitudinal to the transverse directions when the filaments are arranged in the longitudinal direction and the short fibers are arranged in the transverse direction) and preferably bonding the arranged layers with a silane compound composition.