A charger and discharger for a secondary battery includes a secondary battery coupled to an output stage of the charger and discharger, a first converter circuit including a first pulse voltage generator that outputs a first pulse voltage according to a first duty ratio, and a first inductor that outputs a first current in proportion to a value of an integral of the outputted first pulse voltage with respect to time to a positive electrode terminal of the secondary battery, a second converter circuit including a second pulse voltage generator that outputs a second pulse voltage according to a second duty ratio, and a second inductor that outputs a second current in proportion to a value of an integral of the outputted second pulse voltage with respect to time to a negative electrode terminal of the secondary battery, and first and second controllers controlling the duty ratios of the first and second pulse voltage generators, respectively.