To provide a reinforcing short fiber capable of making a fiber-reinforced resin composite material having a high strength, high impact resistance and abrasion resistance without inhibiting the workability in the time of kneading raw materials and mold-processing, and to provide the fiber-reinforced resin composite containing the short fiber.

The fiber-reinforced resin composite is characterized by including the fiber satisfying the following requirements. (a) The single fiber diameter is 20 to 100 μm, and the fiber length is 0.8 to 15 mm. (b) The tensile strength is ≥2,500 MPa, the tensile elastic modulus is ≥50 GPa and the elongation at break is within a 3 to 8% range. (c) The density is ≤1.5 g/cm3. (d) The thermal degradation-starting temperature is ≥300°C. (e) The fiber-mixing ratio is ≥1 vol.%.