The invention relates to a control valve (20) for an apparatus (1) for the variable setting of the control times of gas exchange valves (110, 111) of an internal combustion engine (100), having a valve housing (22) of hollow configuration which has at least one inflow connection (P), at least one outflow connection (T) and at least two working connections (A, B), and having a control plunger (35). In order to retain relatively high flexibility in the design of the control valve components (22, 35) and to simplify the connection of the control valve (20) to the surrounding construction (3), it is proposed to arrange a pressure medium guide insert (27) of hollow configuration within the valve housing (22), and to form at least one pressure medium channel (34) which extends substantially in the axial direction, the pressure medium guide insert (27) engaging around the pressure medium channel (34) at least partially, the pressure medium channel (34) communicating with at least one of the connections (A, B, P, T) and, via a radial opening (33b-d), with the interior of the pressure medium guide insert (27), and the control plunger (35) being arranged within the pressure medium guide insert (27).