The invention provides (1) a reinforcing fiber base material having a weave constituted of both reinforcing fiber filaments arranged in one direction in parallel with each other and auxiliary yarns arranged in another direction, which satisfies the relationship: L=H/cos θ (wherein L is the length of auxiliary yarn covering one reinforcing fiber filament and H is the width of the filament as determined in such a state where the reinforcing fiber filaments are unified only with the auxiliary yarns; and 3°≦θ (in-plane shear strain)≦30°) and wherein 2 g/m2 to 40 g/m2 of an adhesive resin having a glass transition temperature between 0° C. and 95° C. is adhesed to at least one side thereof in spots, lines, or discontinuous lines; (2) a laminate obtained by laminating layers of the above reinforcing fiber base material, wherein the adhesive resin adhesed to each layer of base material partially bonds to a facing layer of base material over the whole surface thereof, with the maximum length of each bonding joint being not less than 1 mm and not more than the width H of a reinforcing fiber filament; and (3) a preform, obtained by shaping the laminate, having a reinforcing fiber volume fraction (Vpf) of 45% to 62%.