A joining device (100) for precast reinforced concrete elements with a dry joint comprising a first group of joining reinforcements (10′) arranged on a first plane and in parallel with one another, each one of said joining reinforcements (10) comprising one reinforcement (1) and two threaded ends (2). The device comprises first coupling means (30) for coupling to the columns (200) arranged between the joining reinforcements (10) and perpendicular to the first plane defined by the joining reinforcements (10) and a plurality of anchoring plates (20) arranged so as to define a closed frame inside of which the joining reinforcements (10) are arranged, and where the inner space defined by the anchoring plates (20) is filled with a structural filler material (concrete, resin, composite, etc.) (50). The anchoring plates (20) comprise a plurality of holes (21), at least one for each threaded end (2), in a position that matches up with the latter, and through which the threaded ends (2) remain accessible. The device comprises second coupling means (40) between the threaded ends (2) and the beam (300) rebars.