A plurality of movable units is arranged in a matrix. First and second electrodes are used in common in the movable units arranged in a column. A plurality of third electrodes, which commonly connects tabular members of the movable units arranged in a row, is formed for each row. The drive circuit selects, in order and one by one, the third electrodes. Subsequently, the drive circuit swings the tabular member by applying a bias voltage to the selected third electrode and applying an approach voltage or a separating voltage to a plurality of the first electrodes and second electrodes. During a predetermined period of maintaining a swinging posture, the voltage applied to the third electrodes is maintained as the bias voltage. The tabular member is returned to a non-swinging state by changing the voltage applied to the third electrodes to a reset voltage after the lapse of the predetermined period.