The present invention relates to a metal fixing instrument for open-type tongue-shaped proximal tibia osteotomy which stably maintains an osteotomy site of the tongue-shaped proximal shinbone and enables other operations to be performed together with the proximal shinbone osteotomy and surgical techniques to be easily performed as the instrument obtains maximum stability by minimum fixation such as minimum volume and size to minimize any damages to soft tissues in the proximal shinbone site. The present invention relates to a metal fixing instrument which is inserted into the osteotomy site of the proximal shinbone to treat arthritis accompanied with varus deformation and limited to an inner side of the knee joint. The metal fixing instrument (10) comprises: a plate-shaped bone fixing part (11) having a predetermined thickness and a bone support (15) vertically formed on a central portion of the bone fixing part (11). The bone support (15) forms an osteotomy part (52) as the tibia is widened after the osteotomy. A front end part is entering into a gap between the tibia and the bone support (15) to support a bone (50) and comprising: a defect part (16) having a groove with a predetermined depth support legs (17) forming both lateral surfaces of the defect part (16) and a nut hole (19) having a screw thread formed perpendicular to the bone fixing part and on an inner lateral surface thereof with a predetermined depth. Both lateral end parts of the support legs (17) are chamfered such that an inclination edge (18) is formed. The bone fixing part (11) causes relatively less irritation to soft tissue and is flexible such that the bone fixing part (11) is formed to be easily attached to the curve-shaped tibia and has screw insertion holes (12, 13) penetrating to allow a fixing means to be formed on both sides thereof.COPYRIGHT KIPO 2016본 발명은 설상 경골 근위부 절골부의 안정성은 좋게 유지하면서, 근위부 경골 부위의 연부조직의 손상을 최소화하도록 최소의 고정(최소의 부피, 크기)으로 최대의 안정성을 얻어 경골 근위부 절골술과 함께 다른 술식의 병행이 가능하도록 하고 또한 수술수
