The invention relates to an instant-heating-type water dispenser. The water dispenser comprises one or more barrels of barreled water, a warm water outlet unit and a hot water outlet unit, the warm water outlet unit and the hot water outlet unit are introduced out by the barreled water, and the hot water outlet unit comprises a heating tank communicated with the barreled water through a water inlet pipe, a temperature sensing meter arranged in the heating tank, a hot water pipe introduced out by the heating tank and a water outlet control unit installed on the hot water pipe; a water inlet control unit is arranged on a water inlet pipe, a steam return pipe is connected to the high position of the heating tank, and the steam return pipe and the water inlet pipe conduct heat exchange in a plate heat exchanger for preheating the water inlet pipe. According to the technical scheme, the water dispenser is in an instant heating type, saves energy and is healthy, the water temperature and water amount can be selected according to actual demands, warm water, hot water and cold boiled water can also be selected, the requirement of environment-friendly drinking of modern people is met, and diverse selection is achieved.