Abstract: A device for assembly and alignment on a first bridge, particularly a timepiece movement plate, arranged in a first plane, the device including a second bridge arranged in a second plane, the second bridge being intended to carry a component, in particular a moving component of a timepiece resonator mechanism, the device including a device for aligning the second bridge on the first bridge, the alignment device including at least two bearing faces of the second bridge arranged orthogonally to the second plane in two different directions, the alignment device further including at least two movable adjustment pieces connected to the first bridge, the adjustment pieces each being configured to contact with one of the bearing faces to position the second bridge in a position on the first bridge, the movable pieces defining a plurality of positions of the second bridge on the first bridge.