Abstract: A device for supporting and guiding a collimator, particularly for a collimator designed to be installed on the ceiling of an aircraft. A collimator follows a complex predefined trajectory in a three-dimensional space (X, Y, Z ) with up to six degrees of freedom, between a given operational position and a stored position. The device includes a first structure (3) attached to the aircraft having three guiding grooves, a first central groove (30) following a plane trajectory in a first plane (X, Y), and two lateral grooves (31, 32) on opposite sides of the central groove which follow second and third trajectories located in two planes perpendicular to the first plane. A second structure (4) rigidly attached to the collimator (1) moves along grooves by means of rollers (8a, 8b, 9a, 9b, 10), the number and shape of which enable the second structure to have six degrees of freedom along the complex trajectory.