An electromagnetic actuating unit (10) of a hydraulic directional control valve (9) is provided having an armature (18) which is arranged such that it can be axially displaced within an armature space (30), and includes a pole core (29) which is arranged in a receptacle (27a) and delimits the armature space (30) in a movement direction of the armature (18). Constructions are provided in order to avoid deposits on a guide surface of the armature (18), as a result of which the dynamics and the response behavior of the actuating unit (10) are increased and hysteresis effects and the risk of a malfunction of the actuating unit are minimized.