A regeneration inverter device for an electric railroad in which a direct current side of a regeneration inverter is connected to an electric car line of the electric railroad, an alternating current load is connected to an alternating current side of the regeneration inverter, and a power storage device is connected to the direct current side of the regeneration inverter, wherein double-throw switches (3, 4) are connected respectively to a positive and a negative electrode on the direct current side of the regeneration inverter to switch a connection between the electric car line and a storage medium of the power storage device, and wherein when discharging, the regeneration inverter is controlled to perform inverter operation by PWM and there is formed a discharging route from the storage medium to the alternating current load, characterized in that: regenerated power generated by a train is stored in the power storage device, wherein the double-throw switch connected to the positive electrode side of the regeneration inverter is switched to a positive electrode side of the electric car line when charging the storage medium and to one end side of the storage medium when discharging, wherein the double-throw switch connected to the negative electrode side of the regeneration inverter is switched to the one end of the storage medium through a reactor (L O) when charging, and to the other end of the storage medium and the negative electrode side of the electric car line when discharging, wherein the regeneration inverter is controlled to perform chopping operation when charging, wherein when the regenerated power generated on the electric car line is charged, there is formed a charging route from the positive electrode side of the electric car line to the storage medium through the double-throw switch connected to the positive electrode side of the regeneration inverter, a switching element of the regeneration inverter, the double-throw switch connected to the negative electrode side of the regeneration inverter and the reactor (L O), and wherein when discharging, the discharging route is formed from the storage medium to the alternating current load through the double-throw switch connected to the positive electrode side of the regeneration inverter, the switching element of the regeneration inverter and a coupled transformer. regenerated power generated by a train is stored in the power storage device, wherein the double-throw switch connected to the positive electrode side of the regeneration inverter is switched to a positive electrode side of the electric car line when charging the storage medium and to one end side of the storage medium when discharging, wherein the double-throw switch connected to the negative electrode side of the regeneration inverter is switched to the one end of the storage medium through a reactor (L O) when charging, and to the other end of the storage medium and the negative electrode side of the electric car line when discharging, wherein the regeneration inverter is controlled to perform chopping operation when charging, wherein when the regenerated power generated on the electric car line is charged, there is formed a charging route from the positive electrode side of the electric car line to the storage medium through the double-throw switch connected to the positive electrode side of the regeneration inverter, a switching element of the regeneration inverter, the double-throw switch connected to the negative electrode side of the regeneration inverter and the reactor (L O), and wherein when discharging, the discharging route is formed from the storage medium to the alternating current load through the double-throw switch connected to the positive electrode side of the regeneration inverter, the switching element of the regeneration inverter and a coupled transformer.