Abstract: Device for detecting parameters of the rotation of a shaft 1 that rotates with respect to a stationary element, there being at least one bearing between the shaft and the stationary element so that the shaft can be mounted to rotate with respect to the stationary element, the said device comprising an encoder means 15 rotated by the rotating shaft, and a sensor means 10 secured to a stationary element and arranged facing and a small air gap away from the encoder means whose passage during rotation is detected by the sensor means. The encoder means and the sensor means are supported by a removable unit 4 independent of the bearing, the said unit being capable of being mounted on the stationary element and having a stationary part 9 supporting the sensor means and a rotating part 13 supporting the encoder means, the rotation of the rotating part being connected to that of the rotating shaft.