The present invention relates to a method for manufacturing a large FRP member and has the following structure. The method for manufacturing a large FRP member, comprising the following steps (A) to (F). They are: setting step (A) of disposing a preform containing a reinforcing
fiber base material on a surface of a molding die; sealing step (B) of covering a molding portion with a bagging material or a mold and providing at least one suction port and at least one resin
injection port for sealing; evacuating step (C) of evacuating the molding portion through the suction port; hot-
air heating step (D) of heating the molding portion by hot air; resin injection step (E) of injecting a thermosetting resin from the resin
injection port for impregnating the reinforcing
fiber base material with the resin while a temperature Tm of the molding die and a temperature Tv of the bagging material or the mold are both set to
room temperature or more, and a difference DeltaT in temperature between the Tm and the Tv is set to 10° C. or less; and curing step (F) of curing the resin by maintaining the molding portion at a predetermined temperature Tpc which is equal to or more than
room temperature. Preferably, the preform described above includes the reinforcing
fiber base material and a resin distribution medium. In addition, it is preferable that in the hot-
air heating step (D), the molding die be placed in a sealed chamber which is heat insulated with a heat insulating material, the hot air be circulated and supplied, and timing of starting the injection of the resin from a plurality of the resin injection ports be controlled in accordance with signals supplied from resin detection sensors provided in the molding die. The present invention provides a method for manufacturing a large FRP member having superior quality at an inexpensive cost and with high production yield, in which non-impregnated portions and voids are unlikely to be formed.