The invention discloses a storage cavity with a double water chamber rapid electric water heater, which relates to a drinking water device. The prior technology has the deficiency of the low temperature of the discharge water. The invention consists of a shell, a bottle seat arranged on the shell and a heating pipe arranged in the shell; wherein, a heater is arranged in the heating pipe; the lower end of the heating pipe is a water inlet end, while the upper end of the heating pipe is a water outlet end, and the water inlet end is connected with the water outlet end. The invention is characterized in that a water tank is arranged at the lower end of the bottle seat, wherein, the water tank is provided with an upper water chamber and a lower water chamber which are separated from each other; the upper water chamber and the lower water chamber are communicated with each other through a water channel; a float valve capable of controlling the make-and-break state of the water channel is arranged at the water channel of the lower water chamber; the lower water chamber is communicated with the water inlet end of the heating pipe to increase the temperature of the discharge water, the maintenance and cleaning are convenient and the operation is reliable.