A measurement device for magnetic resonance applications, including three measurement axes (x, y, z) corresponding to the axis of a main magnetic field and to two transverse axes (x, y) of a closed or half-open space in which are generated radiofrequency electromagnetic fields and magnetic field gradients, characterized in that it includes: - in a measurement case: • a sensor for measuring radiofrequency magnetic fields including an assembly of radiofrequency coils (16, 17) for measuring the components of the radiofrequency magnetic fields along both transverse axes (x, y), • a sensor for measuring magnetic field gradients including three sets of coils (21, 22, 23) for measuring the magnetic field gradients along the three measurement axes (x, y, z) respectively, • a sensor for measuring the radiofrequency electric field including two independent electrically conducting wires (41, 42) mounted in an aligned way, each being surrounded by a material with strong relative dielectric permittivity, • a stage for conditioning the electric signals delivered by the sensor for measuring radiofrequency magnetic fields, by the sensor for measuring magnetic field gradients, by the sensor for measuring the radiofrequency electric field, • a stage for converting the electric signals delivered by the various measurement sensors, into light signals, • an electric power supply source of the conditioning and conversion stages, - a unit for controlling and processing the signals, connected to the stage for conditioning the measurement case via a beam for transmitting light signals, this unit including a stage for converting light signals into electric signals connected to means for synchronously controlling the acquisition of the electric signals delivered by the measurement sensors and corresponding to the electromotive forces generated by the various fields inside the space, - means for displaying and/or recording the electric signals delivered by the sensors. - in a measurement case: • a sensor for measuring radiofrequency magnetic fields including an assembly of radiofrequency coils (16, 17) for measuring the components of the radiofrequency magnetic fields along both transverse axes (x, y), • a sensor for measuring magnetic field gradients including three sets of coils (21, 22, 23) for measuring the magnetic field gradients along the three measurement axes (x, y, z) respectively, • a sensor for measuring the radiofrequency electric field including two independent electrically conducting wires (41, 42) mounted in an aligned way, each being surrounded by a material with strong relative dielectric permittivity, • a stage for conditioning the electric signals delivered by the sensor for measuring radiofrequency magnetic fields, by the sensor for measuring magnetic field gradients, by the sensor for measuring the radiofrequency electric field, • a stage for converting the electric signals delivered by the various measurement sensors, into light signals, • an electric power supply source of the conditioning and conversion stages, • a sensor for measuring radiofrequency magnetic fields including an assembly of radiofrequency coils (16, 17) for measuring the components of the radiofrequency magnetic fields along both transverse axes (x, y), • a sensor for measuring magnetic field gradients including three sets of coils (21, 22, 23) for measuring the magnetic field gradients along the three measurement axes (x, y, z) respectively, • a sensor for measuring the radiofrequency electric field including two independent electrically conducting wires (41, 42) mounted in an aligned way, each being surrounded by a material with strong relative dielectric permittivity, • a stage for conditioning the electric signals delivered by the sensor for measuring radiofrequency magnetic fields, by the sensor for measuring magnetic field gradients, by the sensor for measuring the radiofrequency electric field, • a stage for converting the electric signals delivered by the various measurement sensors, into light signals, • an electric power supply source of the conditioning and conversion stages, - a unit for controlling and processing the signals, connected to the stage for conditioning the measurement case via a beam for transmitting light signals, this unit including a stage for converting light signals into electric signals connected to means for synchronously controlling the acquisition of the electric signals delivered by the measurement sensors and corresponding to the electromotive forces generated by the various fields inside the space, - means for displaying and/or recording the electric signals delivered by the sensors.