A graphite-silicon composite, including: graphite; silicon; and an intermediate layer that is located between the graphite and the silicon, wherein the intermediate layer includes oxygen, carbon and silicon. Furthermore, provided is a method for producing a graphite-silicon composite, including: layering graphite and silicon; and heating the layered graphite and silicon while applying pressure to them, wherein, during heating the layered graphite and silicon while applying pressure to them, an oxygen concentration in the atmosphere is adjusted to 0.2 vol %, the applied pressure is adjusted to 24.5 MPa or higher, and the heating temperature is adjusted to 1260° C. or higher.