The present invention relates to detecting breakage of a shaft of a turbomachine, in particular of the aviation type. The invention relates in particular to a device designed to perform such detection. According to the invention, the device for detecting breakage of a turbomachine shaft comprises: a shaft having an upstream end and a downstream end; a rod having an upstream end and a downstream end, and placed coaxially inside the shaft, the downstream end of the rod being securely fastened to the downstream end of the shaft and the upstream end of the rod being free to rotate relative to the upstream and of the shaft; and a sensor suitable for detecting a difference in speed of rotation between the upstream end of the rod and the upstream end of the shaft.