An escapement mechanism including a stop member between a resonator and two escape wheel sets each subjected to a torque, and each including a magnetized or ferromagnetic track over a period. The stop member includes at least one magnetized or ferromagnetic pole shoe, transversely movable with respect to travel of a surface of the track. The pole shoe or the track creates a magnetic field between the pole shoe and the surface, and the pole shoe is confronted by a magnetic field barrier on the track just before each transverse motion of the stop member actuated by the period action of the resonator. The escape wheel sets are each arranged to cooperate alternately with the stop member, and are connected to each other by a direct kinematic connection.