A bypassing device for a converter, the converter comprising an energy storage unit and a plurality of sub-modules comprising at least one power semiconductor circuit connected to the energy storage unit in parallel and comprising a plurality of power semiconductor switches and free wheel diodes, the bypassing device comprising: a vacuum interrupter tube configured for shorting a first connection terminal and a second connection terminal of a sub-module by contacting a movable contact bolt to a fixed contact bolt when a failure occurs in a specific sub-module of the plurality of sub-modules to which the bypassing device is connectable, and for bypassing a phase current from the specific sub-module in which the failure occurs when the failure occurs in the specific sub-module; and a control device configured for controlling an operation of the vacuum interrupter tube, wherein the control device comprises a permanent magnet having N and S polarities at respective sides from its center, being connected to the movable contact bolt of the vacuum interrupter tube, and moving the movable contact bolt to the fixed contact bolt of the vacuum interrupter tube so as to short the first connection terminal and the second connection terminal of the vacuum interrupter tube, a core having a 'C' type shape and fixedly installed to allow the N and S polarities of the permanent magnet to contact or be separated from both end portions of the 'C' type shaped core respectively, a coil wound on the core, a power source unit supplying power to the coil, and a control unit controlling the power supplied from the power source unit to the coil, wherein the control unit maintains a cut-off state of the power to the coil during normal operation of the specific sub-module so that no magnetism is generated in the core and the both sides of the permanent magnet remain in contact with the both end portions of the 'C' type shaped core due to magnetic forces of N and S polarities of the both sides of the permanent magnet, wherein the control unit controls the power source unit to allow power to be supplied to the coil at the time of occurrence of the failure in the specific sub-module so that the polarities of the both end portions of the 'C' type shaped core are identical to those of the respective sides of the permanent magnet, so that the fixed core pushes the permanent magnet with magnetism induced at the core to short the vacuum interrupter tube to bypass the phase current, and so that even if the power to the coil is cut off after the short in the vacuum interrupter tube, the short in the vacuum interrupter tube is maintained unchanged. a vacuum interrupter tube configured for shorting a first connection terminal and a second connection terminal of a sub-module by contacting a movable contact bolt to a fixed contact bolt when a failure occurs in a specific sub-module of the plurality of sub-modules to which the bypassing device is connectable, and for bypassing a phase current from the specific sub-module in which the failure occurs when the failure occurs in the specific sub-module; and a control device configured for controlling an operation of the vacuum interrupter tube, wherein the control device comprises a permanent magnet having N and S polarities at respective sides from its center, being connected to the movable contact bolt of the vacuum interrupter tube, and moving the movable contact bolt to the fixed contact bolt of the vacuum interrupter tube so as to short the first connection terminal and the second connection terminal of the vacuum interrupter tube, a core having a 'C' type shape and fixedly installed to allow the N and S polarities of the permanent magnet to contact or be separated from both end portions of the 'C' type shaped core respectively, a coil wound on the core, a power source unit supplying power to the coil, and a control unit controlling the power supplied from the power source unit to the coil, wherein the control unit maintains a cut-off state of the power to the coil during normal operation of the specific sub-module so that no magnetism is generated in the core and the both sides of the permanent magnet remain in contact with the both end portions of the 'C' type shaped core due to magnetic forces of N and S polarities of the both sides of the permanent magnet, wherein the control unit controls the power source unit to allow power to be supplied to the coil at the time of occurrence of the failure in the specific sub-module so that the polarities of the both end portions of the 'C' type shaped core are identical to those of the respective sides of the permanent magnet, so that the fixed core pushes the permanent magnet with magnetism induced at the core to short the vacuum interrupter tube to bypass the phase current, and so that even if the power to the coil is cut off after the short in the vacuum interrupter tube, the short in the vacuum interrupter tube is maintained unchanged.