The invention provides a numerical controller capable of displaying and inputting the tool direction relative to a workpiece. The numerical controller controls a five-axis machine which machines a workpiece mounted on a table by means of at least three linear axes and two rotation axes. The numerical controller calculates a tool direction relative to the workpiece as a tool direction vector, roll-pitch-yaw angles, or Euler angles, based on respective positions of the two rotation axes, and displays the tool direction relative to the workpiece on a display, based on the result of the calculation.