A thermoacoustic device includes a sound wave generator, a number of first electrodes and a number of second electrodes. The sound wave generator includes a carbon nanotube structure. The second electrodes and the first electrodes are separately connected to the sound wave generator. The second electrodes and the first electrodes are parallel to each other and are alternately arranged at uniform intervals. A working voltage applied to the first and second electrodes is less than or equal to about 50 volts. The sound wave generator and the first and second electrodes satisfy a formula of 1 ⁢ Ω ≤ R 1 ( n - 1 ) 2 ≤ 125 ⁢ Ω . Wherein R1 represents a resistance of the sound wave generator in the direction from the first electrodes to the second electrodes, and n represents a sum of the total number of the first electrodes and the second electrodes.