To make the orientation of reinforcing fibers more anisotropic to obtain a product low in the strength different of the structure by injecting a slurry mainly containing a thermosetting resin and reinforcing fibers in a casting mold and forcibly removing a liquid portion from the slurry by natural filtering, vacuum filtering or pressure filtering.

When a fiber reinforced plastic product becoming a final product, for example, a member for constituting to a brake part or a clutch part, a gasket or a gear is produced, a casting mold 10 constituted of a base material 1 comprising a water permeable material, the outer frame 2 connected to the peripheral end edge part of the base material 1 to extend upwardly and having grooves for forming outer teeth provided to the inner surface thereof and the inner frame 3 verticaly provided to the central part of the base material 1 is used. A press element 4 is loosely fitted in the casting mold and a slurry mainly containing a thermosetting resin and reinforcing fibers is injected in the casting mold and pressed while a liquid portion is forcibly removed from the slurry by natural filtering, vacuum filtering or pressure filtering to produce a product.