In a mirror driving apparatus, a pair of beam portions includes: a pair of first beams directly adjacent to a reflector to sandwich the reflector between the first beams; and a pair of second beams each coupled to one side of a corresponding one of the first beams, the one side being opposite to the reflector with respect to the corresponding one of the first beams. A plurality of electrodes are spaced from each other on a main surface of each of the first beams, a piezoelectric material being interposed between the main surface and the plurality of electrodes. The first beams are displaceable crosswise to the main surface in respective directions opposite to each other. The pair of second beams is displaceable in a direction connecting the first beams and the second beams, along the main surface of the second beams.