The instrument for artificial knee joint replacement surgery includes a holding mechanism that includes a holding portion having a contact portion to be brought into contact with a contact target of a patient on whom artificial knee joint replacement surgery is to be performed and that holds the patient in a state in which the contact portion is in contact with the contact target, and an indicating mechanism that is attached to the holding mechanism and includes a position identification target indicating portion to be arranged at a position corresponding to a position identification target in a state in which the holding mechanism holds the patient. The position at which the position identification target indicating portion is to be arranged is determined based on a positional relationship between the contact target and the position identification target that is obtained in advance prior to surgery.