PURPOSE: To provide an electric hot water reservoir of an inner container removable type which can prevent a thermal disc incorporating a reservoir body from being fused by local concentration of heat from a sheath heater formed in the thermal disc even though a large capacity heater gives a high boiling rate.

CONSTITUTION: A thermal disc 8 has a size substantially equal to that of the bottom part of an inner container 31, a large capacity boiling sheath heater 8a is annularly formed at the outermost peripheral part of the thermal disc 8, and a temperature holding sheath heater 8b is annularly formed on the inside of the sheath heater 8a. Further, the temperature holding sheath heater 8b has both terminals 8b1 which are circumferentially separated to as to form an opened annular configuration, and the boiling sheath heater 8a has both terminals 8a1 which are inwardly superposed with each other between an annularly separated part between both terminals 8b1 of the temperature holding sheath heater 8b, and the outer periphery of the thermal disc 8, so as to an annular configuration.