A knee joint surgical treatment under an arthroscope includes: contacting a treating portion of an ultrasonic device with an end region to which an ACL or a PCL of a tibia adheres and with a start region to which the ACL or the PCL of a femur adheres, excising the tibia and a remaining ligament of the ACL, or the tibia and a remaining ligament of the PCL, excising the femur and a remaining ligament of the ACL, or the femur and a remaining ligament of the PCL by ultrasonically vibrating the treating portion, thereby exposing footprints of the tibia and the femur; and forming tunnels between the footprint of the tibia and a medial side of a rough surface of the tibia and between the footprint of the femur and an lateral surface of a lateral condyle of the femur.