The indirect internal reforming solid oxide fuel cell system includes an indirect internal reforming solid oxide fuel cell that has a first reformer which produces a reformed gas from a hydrocarbon-based fuel by using a steam reforming reaction, a solid oxide fuel cell which generates electric power by using the reformed gas obtained in the first reformer, and a container which houses the first reformer and the solid oxide fuel cell, the first reformer being disposed in a position to receive heat radiation from the solid oxide fuel cell; a second reformer which is disposed outside the container and produces a reformed gas by reforming a hydrocarbon-based fuel; and a line which leads the reformed gas obtained in the second reformer from the second reformer to an anode of the solid oxide fuel cell.