A support structure for a rotation driving system having a ball balancer includes: a motor having a rotational shaft coupled to a rotational shaft of a rotor; the ball balancer provided on the rotor to reduce oscillating motion of the rotor; and a support part for coupling the motor to a housing, wherein the motor is coupled to the housing via an elastic member on a line in one direction (x-axis) perpendicular to an axial direction (z-axis) of the rotational shaft of the motor, and the motor is allowed to swing about the x-axis due to elastic deformation of the elastic member.