This air handling unit (1) comprises a structural frame (3, 5), and air handling components (15) enclosed within a housing (7), at least one of said components (15) having a rectangular shape arranged orthogonally to an air flow direction (F1, F2), and mounted by its edges (151, 153) on the structural frame. The at least one of the components (15) is mounted by one of its edges (151) on at least one movable rail (17) which is mounted in a sliding manner in a stationary rail (19) integral with the structural frame (3, 5) or the housing (7), the movable rail (17) being extractable with respect to the stationary rail (19) out of the housing (7) so that the component (15) can be extracted from the air handling unit (1).