A controller of an elevator in which space for mounting a power accumulating device can be saved and the controller can be applied to an elevator having no machine room. The controller has a power accumulating device arranged between DC buses connected to a converter and an inverter, and accumulating DC power from the DC buses during a regenerative operation of the elevator and supplying the DC power accumulated to the DC buses during a power operation; and a charging-discharging control for controlling charging and discharging of the power accumulating device with respect to the DC buses. The power accumulating device includes a secondary battery and a DC—DC converter for controlling charging and discharging of the secondary battery, and the secondary battery includes plural cells connected in series. The secondary battery is arranged at any one of four corners within an elevator shaft, near a rail, or near a cable within the elevator shaft.