To obtain a plastic composite paper comprising a polar group- containing thermoplastic resin and a vegetable fiber which are combined by hydrogen bond, having excellent water resistance, rigidity, creep resistance, heat resistance, etc., and to provide a method for producing the same.

A mixed sheet of the polar group-containing thermoplastic resin fine powder and the vegetable fiber is heated or heated and pressurized at a temperature equal to or higher than the softening temperature of the polar group-containing thermoplastic resin.