Abstract: This invention relates to the measurement of thermal conductivity. The measuring probe according to the invention is characterized in that it comprises:a plate defining, on its face of application, areas located on the same plane, occupied by the measurement zones (Z.sub.1, Z.sub.2) which are constituted by conducting segments connected in series from one zone to the other by thermocouples,a plane heating element placed, outside the face of application, in relation with the median zone Z.sub.1,a coating made of electrically insulating matter, covering the measurement zones Z.sub.1, Z.sub.2,a cover made of insulating matter covering the plate,and a mass (M) of heat-insulating matter occupying the volume defined by the plate and the cover. The invention is more particularly applicable to the study of the thermal conductivity of biological tissues.