Geological probing device comprising a hollow probing rod to be extended into the geological matter to be probed, and a measuring probe fitted to the probing rod, said measuring probe comprising sensors for obtaining information about the matter. The measuring probe further comprises a microwave transmitter, arranged to transmit microwaves carrying data from said sensors, said hollow probing rod being adapted to act as a waveguide, guiding the microwaves to an upper orifice of said hollow probing rod. Compared to previously known techniques, the device according to the invention offers a reliable transmission of data under normal working conditions, and without substantive modifications of the probing rod or other equipment.