A heat-resistant fiber paper sheet which is formed from staple fibers made from a heat-resistant organic polymer, undrawn or low ratio drawn para-aromatic polyamide staple fibers, and an organic resin binder and/or fibrids comprising a heat-resistant organic polymer as main components, wherein the amount of said staple fibers is 45 to 97 percent by weight based on the total amount of said heat-resistant fiber paper sheet; the total amount of said organic resin binder and/or said fibrids is 3 to 55 percent by weight based on the total amount of said heat-resistant fiber paper sheet; and said organic resin binder is cured, and/or said undrawn or low ratio drawn para-aromatic polyamide staple fibers and said fibrids are partially softened, deformed and/or melted to exhibit the actions of binders. The obtained heat-resistant fiber paper sheet has excellent heat resistance, excellent heat dimensional stability, excellent plybond strength, an excellent electric insulating property in a high humidity, and the like, has good resin impregnability in spite of having a high bulk density, and is especially suitable for use as a substrate for electric insulating materials or as a substrate for laminates used for electric circuits.