The invention relates to a soft starter (10) for connecting at least one main circuit (12, 14, 16), each of which includes a bypass circuit (20) having a semiconductor switch (22). Said soft starter (10) comprises a control unit (40) for actuating the bypass circuit (20), and the control unit (40) is equipped with a control signal input (44). According to the invention, the control unit (40) has a separate safety signal input (42).