Method for producing fiber-reinforced composite material

A method for producing a fiber-reinforced composite material, comprising:

• a fiber dispersion process of forming a fiber-dispersed resin by kneading a resin with fibers to disperse the fibers in the resin, wherein a weight ratio of the fibers and the resin (fiber/resin) in the fiber dispersion process is 2/8 or more and 5/5 or less;
• and
• a molecular weight reduction process of reducing a molecular weight of the fiber-dispersed resin to produce the fiber-reinforced composite material,
• wherein the molecular weight reduction process, while transporting the fiber-dispersed resin along an outer peripheral surface of a screw body that includes a passage inside, restricts transport of the fiber-dispersed resin with a barrier unit provided between an inlet and an outlet of the passage on the outer peripheral surface to form a resin reservoir, in which a filling rate of the fiber-dispersed resin is 100%, immediately before the barrier unit, apply a shear force to the fiber-dispersed resin with a rotation speed of the screw body set to 1500 rpm or more and 3200 rpm or less, and cause the fiber-dispersed resin to pass from the inlet of the passage to the outlet of the passage.