Abstract: The harness device is used to effect head control of a horse and includes a crown assembly connected to a bit in the horse's mouth via a pair of control lines connectable to a strap that is attached either along the belly or the mane of the horse. The crown assembly is effective to fit over the ears of a horse and includes a poll strap extending across the poll area of the horse's head. The strap is detachably connectable to the cinch of a saddle for extending forward along the horse's belly between the front legs of the horse. The pair of control lines extends from the end of the belly strap to the bit via a movable connection with the crown assembly. This controls the upward movement of the head. A pair of control lines attached to a strap extending along the horse's mane controls the downward movement of the head.