A cold-water generating tank is provided for generating cold water by using the ice thermal storage method and a water cooler equipped with same. The cold-water generating tank includes a tank body which houses, on the inside thereof, an ice storage liquid cooled by means of a cooling unit; a cooling tube provided on the inside of the tank body in order to cool the ice storage liquid housed inside the tank body; and a cold-water generating unit which has a heat exchange tube forming a flow pathway where inflowing water becomes cold water through heat exchange with the ice storage liquid, and has an extension member positioned on the outer circumferential surface of the heat exchange tube in order to widen the area of contact with the ice storage liquid.