A device for resistive measurement of the moisture of a material, which is mineral, rigid and which has open porosity, the device including a block of material of which it is desired to measure the resistance variations as a function of its water content, at least two detection electrodes which are rigid, non-oxidising and bare, applied parallel against the material, and sealed on to the latter by a blend of powder of material and lime, wherein each detection electrode is connected to an electronic unit able to generate a measuring current and an electronic unit able to measure the resistance between the said electrodes.