To provide an operational method for reducing a residual iron when a blast furnace is repaired by which the repairing period is shortened and the repairing cost can be reduced by reducing the residual iron quantity in the furnace when the blast furnace is to be repaired by stopping the blast.

In the operational method for reducing the residual iron at the repairing time of the blast furnace by lowering the stock level and stopping the blast without tapping molten iron in the furnace bottom, an operation having low iron tapping ratio is continued at least for one month before stopping the blast and coke 5 at the furnace core part is dipped into the molten iron 6 so that the residual iron block quantity is reduced at the stopping time of the blast furnace.