Steps S101 and S102 of displaying images which input two-dimensional tomographic images of the lower limb including the knee joint and displays three-dimensional images of the femur and the tibia including the knee joint from the image input, steps S103 to S105 and S106 to S108 of determining artificial joint which determine the artificial joint to be replaced from the three-dimensional images of each knee joint of the femur and tibia, and steps S113 and S114 of parameter determination which determine various parameters used in an artificial knee joint replacement operation using an alignment rod in the marrow to be inserted into the femur based on the artificial joint and reference points of the knee joint determined in steps S103 to S105 of determining femur side artificial joint are performed by a computer.
