An aliphatic polyketone fiber paper comprising aliphatic polyketone fibers and a polyketone fiber paper core material for a printed wiring board are provided. The polyketone fiber paper and the core material have high strength and modulus of elasticity; excellent dimensional stability, chemical resistance, heat resistance, adhesiveness and electrical insulation; and low dielectricity and water absorbance, and are thin, porous, and uniform. A printed wiring board prepared from the core material having a low dielectric constant, dimensional stability, electrical insulation, and properties of being uniformly bored by laser punching is also provided. The aliphatic polyketone fiber paper and the core material for a printed wiring board comprises 1 to 100% by mass of aliphatic polyketone fibers which comprise the repeating unit of the below-mentioned formula (1), the fibers having an average fiber length of 0.5 to 10 mm, an average fiber diameter of 0.1 to 20 μm, a thickness of 5 to 200 μm, a void ratio of 30 to 90%, and a strength per unit mass of 100 MN / kg or more. Also provided is a single layer or multilayer printed wiring board which comprises a core material impregnated or coated with a polymer resin, a low dielectric polymer resin, or a polyphenylene ether-based epoxy resin.—CH2—CH2—CO— (1)