An electric boiler using late-night electricity is disclosed. The electric boiler using late-night electricity comprises a thermal storage tank with an internal space; a partitioning part for partitioning the inside of the thermal storage tank into multiple heating spaces; multiple hot water tanks partitioned by the partitioning part and installed inside the thermal storage tank; a heating part for corresponding to each hot water tank to heat water stored in the hot water tanks; a supplying and transferring part connected to each hot water tank to transfer the heated water from the hot water tanks to the outside; and a recovering and transferring part connected to each hot water tank to transfer recovered water into the hot water tanks.
