A passive jaw exerciser is provided for application of an anatomically applied jaw moving force for pivoting of the jaw at its tempero-mandibular joint or to provide a motion to the jaw which is beneficial in facial orthopedics. A body structure is provided having guide tracks which guide movement of a carriage according to the character of movement that is desired. The carriage is movable by a lever operated push rod to thereby cause corresponding movement of a mandibular jaw piece supported by a carriage relative to a maxillary jaw piece supported by the exerciser body. The position of engagement between the lever and the push rod is adjustable through selection of any one of a number of spaced slots that are formed in parallel webs of the lever structure.