Disclosed is a balance training apparatus for applying an exercise load to a subject, which comprises a seat adapted to allow the subject to sit thereon, a rocking mechanism for rockingly moving the seat, and a phase changer. The rocking mechanism includes a plurality of converters adapted to receive a driving force transmitted from a common driving source so as to operate in an interlocked relationship with each other, and convert the driving force from the driving source to a rocking motion having movement directions intersecting with each other. The phase changer is adapted to selectively connect and disconnect the transmission of the driving force to first converter consisting of a part of the plurality of converter, so as to change a phase relationship in rocking motion between the first converter, and second converter consisting of the rest of the plurality of converter. The seat with a subject thereon can be mockingly moved in a variety of rocking patterns according to variously changed phase relations.