Abstract: A device for localizing and executing resection cuts on the femur (1) for preparing an implantation of a total endoprosthetic knee joint is provided. The device includes a reference device (5) adapted to be releasably attachable to the femur (1) in the distal area of the femur (1). Alignment of the reference device (5) relative to the femur (1) should be accurately positionable. An adjustment device (10) is connected to the reference device (5). The adjustment device (10) is movable relative to the reference device (5) and is provided with a linearly movable base part (10g) for the attachment of an instrument (11, 14). A first drive device (5v, 21) linearly moves the adjustment device (10) relative to the reference device (5) in the direction (10b) of a first axis (X) of a system of coordinates (X, Y, Z). A second drive device (10f, 17) linearly moves the base part (10g) in the direction (10d) of another, second axis (Y) of said system of coordinates (X, Y, Z).