A molding method for a composite sheet used for manufacturing a thermosetting resin prepreg sheet in which a thermosetting resin material is impregnated into a fiber sheet, the molding method comprising: bringing a resin transfer sheet in which a thermosetting resin material is carried on one surface of a transfer sheet into contact with one surface of the fiber sheet to be stacked on the fiber sheet, said fiber sheet being composed of fibers wherein a density of fibers included in a fiber bundle is ρ c g/cm 3 and said fiber sheet having a base weight of W C g/m 2, said thermosetting resin material having a density of ρ R g/cm 3 and a predetermined thickness of the thermosetting resin material is such that a base weight of the thermosetting resin material carried on the transferred sheet is W R g/m 2; subjecting the resin transfer sheet and the fiber sheet in the stacked state to a heating treatment or heating and pressurizing treatment thereby heating the resin transfer sheet and the fiber sheet to a heating temperature; and subjecting the resin transfer sheet and the fiber sheet in the heated and stacked state to a cooling treatment or cooling and pressurizing treatment; characterized in that by subjecting the resin transfer sheet and the fiber sheet in the heated and stacked state to a cooling treatment or cooling and pressurizing treatment the temperature of the resin transfer sheet and the fiber sheet is reduced from the heating temperature to a normal temperature at which the viscosity of the thermosetting resin material is 10000 Pa·s or more; so that the thermosetting resin material is transferred to the fiber sheet and a portion of the thermosetting resin material is formed in a layered state on one surface side of the fiber sheet and adhered so as to be integrated to form said composite sheet, and so that a thickness of the composite sheet is thicker than [{(W C /ρ C)/1000}+{(W R /ρ R)/1000}] mm. bringing a resin transfer sheet in which a thermosetting resin material is carried on one surface of a transfer sheet into contact with one surface of the fiber sheet to be stacked on the fiber sheet, said fiber sheet being composed of fibers wherein a density of fibers included in a fiber bundle is ρ c g/cm 3 and said fiber sheet having a base weight of W C g/m 2, said thermosetting resin material having a density of ρ R g/cm 3 and a predetermined thickness of the thermosetting resin material is such that a base weight of the thermosetting resin material carried on the transferred sheet is W R g/m 2; subjecting the resin transfer sheet and the fiber sheet in the stacked state to a heating treatment or heating and pressurizing treatment thereby heating the resin transfer sheet and the fiber sheet to a heating temperature; and subjecting the resin transfer sheet and the fiber sheet in the heated and stacked state to a cooling treatment or cooling and pressurizing treatment; characterized in that by subjecting the resin transfer sheet and the fiber sheet in the heated and stacked state to a cooling treatment or cooling and pressurizing treatment the temperature of the resin transfer sheet and the fiber sheet is reduced from the heating temperature to a normal temperature at which the viscosity of the thermosetting resin material is 10000 Pa·s or more; so that the thermosetting resin material is transferred to the fiber sheet and a portion of the thermosetting resin material is formed in a layered state on one surface side of the fiber sheet and adhered so as to be integrated to form said composite sheet, and so that a thickness of the composite sheet is thicker than [{(W C /ρ C)/1000}+{(W R /ρ R)/1000}] mm.