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).
