Abstract: An auxiliary power steering unit, especially for motor vehicles, contains a control valve (1) made as a rotary slide valve for controlling a pressure medium conveyed by a servopump (3) out of a tank (4) to and from the pressure chambers of a servomotor (2). Control valve (1) reveals two feedback chambers (10, 11) that are connected via one, each, fixed throttle (12, 13) and a common throttle (14) to a pressure line (15) of the servopump (3). The feedback pressure that takes effect in the feedback chambers (10, 11) can be limited to a maximum value by a cutoff valve (18). The cutoff valve (18) is made as pressure balance whose response pressure can be adjusted from the outside without dismantling.