A fixing instrument for an open-type distal tibial osteotomy according to an exemplary embodiment of the present invention is installed on a tibia incised by the open-type distal tibial osteotomy, and the fixing instrument includes: a body portion which is in close contact with the tibia and has a plurality of coupling holes and an oblong hole； a head portion which is connected to one end of the body portion and has a plurality of coupling holes； screws which are inserted into the coupling holes； and a block which is detachably installed in the oblong hole by using a sliding screw, in which the head portion is formed to have a predetermined angle based on a lower surface of the head portion, and the other end of the body portion is formed to have a predetermined angle based on a lower surface of the body portion.
