A three-dimensional ultrasound scanner comprising: a scanner case comprising an upper space and a lower space; a transducer unit housed in the lower space of the scanner case and hung on a swing axis; a motor for generating a rotary power housed in the upper space of the scanner case, wherein a rotational axis of the motor is perpendicular to the swing axis; and a swing mechanism connecting the transducer unit and the motor and configured to transmit the rotary power of the motor to the transducer unit to swing the transducer unit about the swing axis, wherein the swing mechanism comprises: an arm holder connected to the rotational axis of the motor; an arm connected to the arm holder, and configured to swing within a certain angular range about the rotational axis depending on rotation of the motor; a link, attached to the arm, for moving in unison with the arm; and a shaft connected to the link and mounted on top of the transducer unit, the shaft extended from the link to the transducer unit in a direction substantially parallel to the rotational axis of the motor, and configured such that the swing movement of the arm delivered to the shaft via the link causes the shaft to swing around the rotational axis of the motor and thereby thrusts the transducer unit sideways such that the transducer unit swings about the swing axis. a scanner case comprising an upper space and a lower space; a transducer unit housed in the lower space of the scanner case and hung on a swing axis; a motor for generating a rotary power housed in the upper space of the scanner case, wherein a rotational axis of the motor is perpendicular to the swing axis; and a swing mechanism connecting the transducer unit and the motor and configured to transmit the rotary power of the motor to the transducer unit to swing the transducer unit about the swing axis, wherein the swing mechanism comprises: an arm holder connected to the rotational axis of the motor; an arm connected to the arm holder, and configured to swing within a certain angular range about the rotational axis depending on rotation of the motor; a link, attached to the arm, for moving in unison with the arm; and a shaft connected to the link and mounted on top of the transducer unit, the shaft extended from the link to the transducer unit in a direction substantially parallel to the rotational axis of the motor, and configured such that the swing movement of the arm delivered to the shaft via the link causes the shaft to swing around the rotational axis of the motor and thereby thrusts the transducer unit sideways such that the transducer unit swings about the swing axis. an arm holder connected to the rotational axis of the motor; an arm connected to the arm holder, and configured to swing within a certain angular range about the rotational axis depending on rotation of the motor; a link, attached to the arm, for moving in unison with the arm; and a shaft connected to the link and mounted on top of the transducer unit, the shaft extended from the link to the transducer unit in a direction substantially parallel to the rotational axis of the motor, and configured such that the swing movement of the arm delivered to the shaft via the link causes the shaft to swing around the rotational axis of the motor and thereby thrusts the transducer unit sideways such that the transducer unit swings about the swing axis.