Abstract: A tridimensional electrostatic accelerometer comprises a cube-shaped test ight. On each of the six faces of the cube is a pair of conducting electrodes. A hollow cage accommodates the test weight and twelve electrodes on the cage to form, with the test weight electrodes, three sets of four capacitors C.sub.ij, where i varies from 1 to 4 and j is x, y and z respectively. Measurements are made for each value of j of the sums and differences of the capacities(C.sub.1 -C.sub.2).sub.j (C.sub.3 -C.sub.4).sub.j(C.sub.1 +C.sub.2).sub.j (C.sub.3 +C.sub.4).sub.jFrom these quantities voltages are derived for positioning the test weight. The voltages are applied selectively to the electrodes of the set of capacitors C.sub.ij.