PROBLEM TO BE SOLVED: To provide an artificial knee joint installing jig that is usable without inserting an intramedullary rod into a medullary cavity.SOLUTION: An artificial knee joint installing jig (1) according to the invention includes: a femur fitting part (2) that is fitted to a femur and a jig body (4) that contacts a proximal end surface of tibia which is formed by excision. The femur fitting part (2) and the jig body (4) are connected with each other in a manner capable of relatively moving in a direction perpendicular to the proximal end surface of tibia and engaging with each other at an arbitrary relative position, so as to generate a prescribed tension state at a ligament connecting the tibia with the femur. The femur fitting part (2) includes a plate member (6) that is attached to a distal end surface of tibia which is formed by excision. The plate member (6) includes: a first contact surface (6a) that contacts a distal end surface of femur and a second contact surface (6b) that is located on an opposite side parallel to the first contact surface (6a). The jig body (4) contacts the second contact surface (6b).
