Abstract: A method and an apparatus to position translatable mirrors in a laser gyrometer device is provided. For example, the method includes prepositioning three mirrors at an initial triplet of predetermined respective positions, simultaneously moving in translation the three mirrors within ranges having an amplitude that is lower than or equal to an intermode of an optical cavity, to ensure that the amplification medium provides a maximum gain. The intensities of the laser waves flowing respectively through each of the optical cavities are measured for each triplet of positions. The method includes determining, from the three triplets of mirror positions, the length of each of the three cavities at which the cavity provides a maximum intensity. The method includes determining a single final triplet of mirror positions for simultaneously imparting to the three lengths at which they provide a maximum intensity. The method includes positioning the mirrors according to the final position triplet.