PURPOSE: To form a fiber reinforced resin molded product large in reinforcing fiber content and excellent in mechanical characteristics in good efficiency, by a method wherein a mold is filled with a thermosetting resin composition having a reinforcing fiber contained therein and compressed when said resin composition reaches specific viscosity by heating.

CONSTITUTION: A thermosetting resin composition shows the viscosity change as shown by a drawing with the rising in a temp. is used. That is, a composition prepared by mixing 35W50vol% of a reinforcing fiber with a fiber length of 1W 100mm (e.g., a carbon fiber, a glass fiber) (B) and 0W2wt% of a non-fibrous filler (C) in a thermosetting resin composition (e.g., epoxy resin compounded with a curing agent) (A) is put in a mold 1 and the mold 1 and a mold 2 are compressed when the viscosity of the resin composition (a) reaches 10W1,000 poise by heating to fill the mold cavity to perform molding.