The purpose of the present invention is to prevent dislodgement of artificial bone or an increase in the backward inclination angle of an articular surface even when a vertical load is applied to a joint in an upright state after treatment. The invention is a bone plate (1) provided with: a strip-shaped main body (1a) that is fixed along the longitudinal direction of a tibia to an obliquely anterior medial surface of the tibia, lower than a cut formed in the medial surface of the tibia a transverse section (1b) fixed along a direction intersecting with the longitudinal direction of the tibia to the medial surface of the tibia, higher than the cut and a coupling section (1c) coupling together the main body (1a) and the transverse section (1b). A plurality of screw holes (5, 6, 7) that are arrayed at intervals from one another and penetrate through the thickness direction are provided to the transverse section (1b) and the main body (1a).
