The invention relates to an acoustic method and device for localized, contactless, measurement of elastic and dissipative non-linearities and dynamic non-linear 
viscoelasticity in a medium subjected to a low-frequency acoustic stress and probed by ultrasonic pulses or wave trains. For this purpose, the invention relates to an acoustic, localized and contactless device for measuring elastic and dissipative nonlinearities and 
viscoelasticity of a specimen (2), characterized in that it comprises: means (10, 20, 22, 24) for transmitting a low-frequency 
acoustic wave (24a) and means (26, 34, 30) for receiving said low-frequency 
acoustic wave, which means are capable of creating a low-frequency periodic variation of the 
hydrostatic pressure in the specimen (2); means (10, 12, 14) for generating high-frequency ultrasonic pulses (14a) and means (16, 28, 30) for receiving said pulses; and an analysis unit (32) that includes a model for calculating the modulations in the 
time of flight and in the amplitude of the ultrasonic pulses (14a) that are induced by the low-frequency 
acoustic wave (24a) passing through the specimen (2), so as to quantify the elastic and dissipative non-linearities and the non-linear 
viscoelasticity of the specimen (2).