A balance training apparatus, which is preferably used for training a body balance function and a locomotive function of a user, and for rehabilitation for lumbago prevention, is provided. This apparatus has a seat for the user and a driving unit for driving the seat. The driving unit comprises a drive source and a power transmission unit for converting an output of the drive source into a horse-riding motion, which is a combination of a rectilinear reciprocating motion in a forward and backward direction (X) of the seat, a first pivotal reciprocating motion (.theta.y) about an axis extending in a horizontal direction substantially perpendicular to the forward and backward direction, and a second pivotal reciprocating motion (.theta.x) about an axis extending in the forward and backward direction, and transferring the horse-riding motion to the seat.