Recently, the number of robot-assisted orthopaedic systems has been increased. As one of the backgrounds, it is considered that the error between the plan and the result of bone cutting is not constant because of the individual surgeon's skill. The authors developed a bone cutting robot which has 7 degrees of freedom. A prototype of the total system for minimally invasive knee arthroplasty, including navigation system, was implemented. In this paper, the detail of the minimally invasive knee arthroplasty system is described, the resection experiment for a cadaver was performed successfully