To enable displaying of superb moisture permeability and high strength and reduce the emitted quantity of formaldehyde by applying a curable resin and a formaldehyde scavenger to a fiber base material consisting of palm fibers as a main component and molding the base material by compression.

Split palm fibers are placed in plural hoppers and a curable resin and a formaldehyde scavenger are previously supplied under pressure to a spray gun. Then the palm fibers are dropped and supplied to the surface of a belt conveyor from each of the hoppers simultaneously with the operation of the belt conveyor. Next, the palm fibers are entangled by a needle punching device and further the curable resin and the formaldehyde scavenger are sprayed to the entangled palm fibers to form a fibrous mat. After that, the fibrous mat is thermally molded by compression using a heat press or the like to obtain a fibrous plate. Thus it is possible to manufacture moldings which show outstanding moisture permeability and high strength and at the same time, emit a very small quantity of formaldehyde and therefore are friendly to living environments.