The present invention relates to a bone fusion device that can draw a distant bone body in a surgery direction toward a close bone body in the surgery direction while combining the adjacent bone bodies. The bone fusion device comprises: a bone screw that has a shank that extends in the longitudinal direction and has a circular cross-section, a screw section formed on one end portion of the shank, and an adjustment internal thread section formed on an opposite end portion of the shank； a washer that has a through-hole into which the opposite end portion of the shank is inserted and has a cross-sectional area lager than that of the screw； and an adjustment screw that is screw-coupled with the adjustment internal thread section through the through-hole of the washer.
