An air-pulse generating device includes a first cell and a second cell. The first and second cells are disposed next to each other. Each cell includes a first flap and a second flap. The second flap of the first cell is disposed next to the first flap of the second cell. The first flap of the second cell is driven by a first demodulation-driving signal, and the second flap of the first cell is driven by a second demodulation-driving signal. A first transition period of the first demodulation-driving signal overlaps with a second first transition period of the first demodulation-driving signal.