A control valve according to the present invention is configured such that when a third opening part, which is an auxiliary opening part, and a third discharge opening, which is an auxiliary connection opening, do not overlap, the third opening part and a continuous discharge opening overlap. Thus, for example, when a flow rate of cooling water for continuous circulation is required, such as during a cold start, cooling water guided through an internal passage is discharged via the continuous discharge opening in addition to cooling water guided from a bypass passage, thereby ensuring a sufficient flow rate of cooling water for continuous circulation.