A thermoacoustic device includes a sound wave generator, a signal element and a support element. The sound wave generator includes a carbon nanotube structure. The signal element is configured to transmit a signal. The carbon nanotube structure is configured to receive the signal and generate a sound wave. The support element includes a metal substrate and an insulating layer located on the metal substrate. The insulating layer is sandwiched between the metal substrate and the sound wave generator. The thermoacoustic device further includes two electrodes electrically connected to the carbon nanotube structure.