Abstract: A method of improving sound quality of an ultrasonic speaker device includes: a first operation of removing a low frequency component of an input audio signal by using a high pass filter; a second operation of correcting a response characteristic of a signal obtained by removing the low frequency component, for each frequency band by using an equalizer; a third operation of adjusting a sound pressure level of a signal obtained by correcting the response characteristic for each frequency band; and a fourth operation of controlling a signal magnitude not to increase above a particular level by using a limiter, in order to prevent a signal clipping that may occur in the second operation and the third operation. An audio signal of improved sound quality may be transmitted to a listener by applying a sound quality improving method suitable for the characteristics of a super-directional ultrasonic speaker.