A conveyor system, comprising: a suction device including a plurality of suction units, each suction unit having an opening and configured to suction a flat transport target article elongated in one direction by negative pressure through the opening; a moving device configured to move the suction device, the moving device including a turning-over section configured to rotate the suction device about an axis in an approximately horizontal direction; and a control device configured to control the suction device and the moving device, characterized in that: when the control device determines that a front side and back side of the transport target article needs to be turned over, the control device is configured to control the moving device and the suction device to suction the transport target article so that an approximate center of the opening of at least one suction unit among the plurality of suction units is located on a first imaginary line, and the remaining suction unit/s is/are located on one end side in a longitudinal direction of the transport target article with respect to the first imaginary line, the first imaginary line being an imaginary line running through an approximate center between both ends in a longitudinal direction of an upper surface of the transport target article and approximately parallel to a shorter direction of the upper surface of the transport target article; to control the turning-over section to be in a front-back reversing orientation in which: the remaining suction unit/s is/are positioned above the first imaginary line along a gravity direction; another end opposite to one end side of the transport target article in the longitudinal direction suctioned by the remaining suction unit/s is located below the first imaginary line along the gravity direction; and the transport target article is inclined with respect to the gravity direction, and to perform control so that suction of the transport target article by the suction units is released after the suction device is in the front-back reversing orientation. a suction device including a plurality of suction units, each suction unit having an opening and configured to suction a flat transport target article elongated in one direction by negative pressure through the opening; a moving device configured to move the suction device, the moving device including a turning-over section configured to rotate the suction device about an axis in an approximately horizontal direction; and a control device configured to control the suction device and the moving device, characterized in that: when the control device determines that a front side and back side of the transport target article needs to be turned over, the control device is configured to control the moving device and the suction device to suction the transport target article so that an approximate center of the opening of at least one suction unit among the plurality of suction units is located on a first imaginary line, and the remaining suction unit/s is/are located on one end side in a longitudinal direction of the transport target article with respect to the first imaginary line, the first imaginary line being an imaginary line running through an approximate center between both ends in a longitudinal direction of an upper surface of the transport target article and approximately parallel to a shorter direction of the upper surface of the transport target article; to control the turning-over section to be in a front-back reversing orientation in which: the remaining suction unit/s is/are positioned above the first imaginary line along a gravity direction; another end opposite to one end side of the transport target article in the longitudinal direction suctioned by the remaining suction unit/s is located below the first imaginary line along the gravity direction; and the transport target article is inclined with respect to the gravity direction, and to perform control so that suction of the transport target article by the suction units is released after the suction device is in the front-back reversing orientation. when the control device determines that a front side and back side of the transport target article needs to be turned over, the control device is configured to control the moving device and the suction device to suction the transport target article so that an approximate center of the opening of at least one suction unit among the plurality of suction units is located on a first imaginary line, and the remaining suction unit/s is/are located on one end side in a longitudinal direction of the transport target article with respect to the first imaginary line, the first imaginary line being an imaginary line running through an approximate center between both ends in a longitudinal direction of an upper surface of the transport target article and approximately parallel to a shorter direction of the upper surface of the transport target article; to control the turning-over section to be in a front-back reversing orientation in which: the remaining suction unit/s is/are positioned above the first imaginary line along a gravity direction; another end opposite to one end side of the transport target article in the longitudinal direction suctioned by the remaining suction unit/s is located below the first imaginary line along the gravity direction; and the transport target article is inclined with respect to the gravity direction, and to perform control so that suction of the transport target article by the suction units is released after the suction device is in the front-back reversing orientation.