An ultrasonic experimental device allowing to study the initiation of cracks, in the gigacyclic domain, for rolling contact fatigue has been developed. This device thus makes it possible to carry out 20,000 traction-compression cycles per second, the study of a billion cycles is therefore reduced to 14 hours. In addition, the trivialization of cameras with very short exposure times (<1 µs) coupled with recent progress in the field of micrometric speckles makes it possible to use image correlation for this type of study.