A fiber-reinforced composite forming method comprising: an alignment step of aligning a fiber base material (FB1, FB2) in which a core part including an elastic long foam and a cover member for sealing the foam is accommodated in a hollow part, in a forming die; a sealing step of sealing the fiber base material (FB1, FB2) in the forming die to form a sealed space; an injection step of suctioning air in the sealed space formed by the sealing step, reducing a pressure of the sealed space, and injecting a thermosetting resin material into the fiber base material (FB1, FB2) sealed in the sealed space; a curing step of heating and curing the thermosetting resin material injected into the fiber base material (FB1, FB2) by the injection step; a detachment step of detaching a fiber-reinforced composite including the thermosetting resin material cured by the curing step and the fiber base material (FB1, FB2), from the forming die; and a removal step of reducing a pressure of an internal space sealed by the cover member so that the foam contracts, and removing the core part accommodated in the hollow part of the fiber-reinforced composite wherein in the sealing step, a resin injection line connected to a supply source of the thermosetting resin material and the sealed space are caused to communicate with each other, and a suction line connected to a suction source and the sealed space are caused to communicate with each other, in the injection step, the thermosetting resin material is injected into the fiber base material (FB1m FB2) via the resin injection line by reducing the pressure of the sealed space via the suction line; and characterized in that, in the curing step, the internal space is maintained at an atmospheric pressure when the thermosetting resin material is heated. an alignment step of aligning a fiber base material (FB1, FB2) in which a core part including an elastic long foam and a cover member for sealing the foam is accommodated in a hollow part, in a forming die; a sealing step of sealing the fiber base material (FB1, FB2) in the forming die to form a sealed space; an injection step of suctioning air in the sealed space formed by the sealing step, reducing a pressure of the sealed space, and injecting a thermosetting resin material into the fiber base material (FB1, FB2) sealed in the sealed space; a curing step of heating and curing the thermosetting resin material injected into the fiber base material (FB1, FB2) by the injection step; a detachment step of detaching a fiber-reinforced composite including the thermosetting resin material cured by the curing step and the fiber base material (FB1, FB2), from the forming die; and a removal step of reducing a pressure of an internal space sealed by the cover member so that the foam contracts, and removing the core part accommodated in the hollow part of the fiber-reinforced composite wherein in the sealing step, a resin injection line connected to a supply source of the thermosetting resin material and the sealed space are caused to communicate with each other, and a suction line connected to a suction source and the sealed space are caused to communicate with each other, in the injection step, the thermosetting resin material is injected into the fiber base material (FB1m FB2) via the resin injection line by reducing the pressure of the sealed space via the suction line; and characterized in that, in the curing step, the internal space is maintained at an atmospheric pressure when the thermosetting resin material is heated.