An osteotomy assistance kit includes a bone treatment assistance device and an attaching position confirmation device. The attaching position confirmation device includes a feature point indication rod to be applied via a tip portion to a feature point of the bone, a rod support unit that removably supports the feature point indication rod such that the tip portion is indicating the feature point of the bone, and a second support member that movably supports the rod support unit and indicates one of scales on the rod support unit. The bone treatment assistance device includes cutting slits, and first guide holes that guides first rods set to a predetermined positional relation. The second support member of the attaching position confirmation device is attached to the protrusion of the bone treatment assistance device.
