Abstract: The invention relates to apparatus for detecting the stuck point of a conduit, such as drill pipes, in a borehole while eliminating any stress on the detection means during the measurement. A two-part body member is suspended from a cable with the two parts (23 and 24) mounted movably with respect to each other. Each part is anchored independently in the drill pipes and movements between these parts are detected when stresses are applied to the drill pipes (11) from the surface. After anchoring, a spring, designed to bias the two parts of the body member toward each other, is disconnected from the top part of the body member. An angular detection means is mounted between a mobile sleeve and the top part of the body member. Before the measurement, the sleeve is uncoupled from the bottom part and reset in relation to the top part. During the measurement, the sleeve is blocked in the bottom part.