An optical device for measuring the rotation of an object, comprising: - a light source capable of emitting a collimated incident light beam propagating in an incident direction, - a reflecting plane optical interface (13, 23) intended to be fastened to the object, the rotation of which it is desired to measure, and capable of receiving a part of the incident beam (8, 8') and of forming a first reflected beam, - a cube-corner retroreflector intended to be fastened to the object, said cube corner comprising reflecting plane faces (14, 14', 14") capable of receiving a part of the incident beam (8, 8") and of forming a second reflected beam in a direction parallel to the incident direction, - a sensing system capable of measuring, on the one hand, the displacement Δ 1 of the first reflected beam, reflected by the reflecting plane optical interface (13, 23) and, on the other hand, the displacement Δ 2 of the second reflected beam, reflected by the reflecting faces (14, 14', 14") of the cube corner, the displacements Δ 1 and Δ 2 being respectively measured with respect to an initial position of the first reflected beam and of the second reflected beam, and characterized in that it comprises: - a processing system adapted for calculating, as a function, on the one hand, of the measurement of the displacement Δ 1 and of the distance D 1 between the sensing system and the reflecting plane optical interface (13, 23) and, on the other hand, of the measurement of the displacement Δ 2 and of the distance D 2 between the sensing system and the cube corner, a measurement of the rotation α of the object between an initial position and a measurement position, said measurement of the rotation α of the object being function of an arithmetic sum of the measurement of the displacement Δ 1 and of the measurement of the displacement Δ 2, said arithmetic sum being divided by the distance D 2 between the cube corner and the sensing system, so that said measurement of the rotation α of the object is corrected from a parasitic rotation β of the source relatively to the object and insensitive to the rotations of the light source. - a light source capable of emitting a collimated incident light beam propagating in an incident direction, - a reflecting plane optical interface (13, 23) intended to be fastened to the object, the rotation of which it is desired to measure, and capable of receiving a part of the incident beam (8, 8') and of forming a first reflected beam, - a cube-corner retroreflector intended to be fastened to the object, said cube corner comprising reflecting plane faces (14, 14', 14") capable of receiving a part of the incident beam (8, 8") and of forming a second reflected beam in a direction parallel to the incident direction, - a sensing system capable of measuring, on the one hand, the displacement Δ 1 of the first reflected beam, reflected by the reflecting plane optical interface (13, 23) and, on the other hand, the displacement Δ 2 of the second reflected beam, reflected by the reflecting faces (14, 14', 14") of the cube corner, the displacements Δ 1 and Δ 2 being respectively measured with respect to an initial position of the first reflected beam and of the second reflected beam, and characterized in that it comprises: - a processing system adapted for calculating, as a function, on the one hand, of the measurement of the displacement Δ 1 and of the distance D 1 between the sensing system and the reflecting plane optical interface (13, 23) and, on the other hand, of the measurement of the displacement Δ 2 and of the distance D 2 between the sensing system and the cube corner, a measurement of the rotation α of the object between an initial position and a measurement position, said measurement of the rotation α of the object being function of an arithmetic sum of the measurement of the displacement Δ 1 and of the measurement of the displacement Δ 2, said arithmetic sum being divided by the distance D 2 between the cube corner and the sensing system, so that said measurement of the rotation α of the object is corrected from a parasitic rotation β of the source relatively to the object and insensitive to the rotations of the light source.