Abstract: Apparatus for resectioning knee condyles, enabling a prosthesis to be fitted, comprising a femoral cutting device (12) comprising a support element (14), a femoral cutting blade guide (21, 24, 30) fixed and vertically adjustable in relation to the support element, a femoral intramedullary rod (28) for orienting and centering said device and feeler means (56, 57, 78) for the anterior cortical femur portion (58, 79). The cutting blade guide includes at least two blocks (21, 24, 30) movable in relation to the support element and vertically adjustable in relation to the support element and vertically adjustable in relation to one another. One of the blocks comprises means for guiding at least one anterior, posterior, anterior chamfer or posterior chamfer cut, the block also having means for guiding the remaining cutting operations.