A directional drilling tool comprising an orientation spear point having a spear axis. The delta log is organized into blocks, which are the largest division in the delta log. If it is determined that the amount of sheets of paper that remain in the first paper-feeding unit has reached the predetermined amount, control is performed so that the paper-feeding unit that is used for printing should be changed after the ejection of the last one of a plurality of sheets of paper that are included in one set thereof set in the first paper-feeding unit.