In a swing exercise machine having a seat, a seat driving apparatus that moves the seat along a locus formed by a combination of a periodic swing motion around an anteroposterior swing shaft and a periodic swing motion around a transverse swing shaft, and a control circuit that can control rotation speed and rotation direction of a motor. The control circuit can switch the rotation direction of the motor, so that the seat can be moved in a reverse direction along the locus. Since the human body is asymmetrical in the anteroposterior direction, the regions of the human body where muscle activities occur when the seat is moved in the reverse direction are different from those when the seat is moved in a normal direction. Thereby, it is possible to vary the effect of the swing exercise on the human body.