Abstract: The invention relates to an NMR device for detection of resonant protons contained in an object. The device comprises permanent magnets for producing a static and uniform magnetic field in a region located outside the device with respect to which the object will be positioned, these permanent magnets being laid out around an axis on which the said region is located, such that their magnetization direction is directed towards the said region and such that the magnetization values of the permanent magnets combine their effects to produce the static and uniform magnetic field in the said region. The device also comprises means for emission of an electromagnetic signal to the said region and reception of an electromagnetic signal returned from the said region in response to the emitted signal, these means being located inside the space delimited by the said permanent magnets.