Abstract: The invention relates to a time-controlled opening device for vehicle seat belt buckles. In the event of an accident and once the airbags (7a) have inflated, the vehicle (7) sends a signal to a unit (1) which in turn supplies current to a first module (5) which holds same for a period of time pre-determined in the delay timer (5) thereof and, once the time has elapsed, supplies the current to a second module which is associated with each of the elements (2) powering different electromagnets (6), retracting a part (6a) at the respective cores thereof, thereby exerting sufficient magnetic pull to disengage each hook (3) and generate the automatic release of the buckles (4).