Abstract: A device for detecting cracks in steel slabs leaving continuous casting, which comprises two crack detecting units placed on either side of the passage of a slab leaving continuous casting and two descaling and cooling units located upstream of the detection units. Each detection unit comprises a mobile frame and a head which slides vertically with respect to the frame and which bears one vertical sensor and three horizontal sensors. The sensors are induction coils placed in a container which is surrounded by a forwardly open metal casing. One application of the device is the automatic switching of defective slabs towards a reprocessing unit.