A sound quality adjustment apparatus of an approaching vehicle audible system that generates a signal of a notification sound, which is emitted from a sounding device provided in an electric vehicle that generates at least part of driving force by use of a motor to the outside of the electric vehicle, is provided with a sound element storage unit that stores sound element data forming an element of the notification sound; a sound-source sound quality extraction unit that analyses the sound element data so as to extract a characteristic value related to the sound quality of a sound element; a parameter setting unit that obtains a parameter for converting the sound element data in accordance with vehicle information, by use of the characteristic value extracted by the sound-source sound quality extraction unit; and a parameter storage unit that stores the parameter obtained by the parameter setting unit.