A liquid discharging apparatus comprising: a conveying unit configured to convey a recording medium (P); a liquid discharging head including nozzles arranged linearly and configured to discharge liquid onto the recording medium (P) conveyed by the conveying unit ; a scanner installed in such a manner that a main-scanning direction of the scanner is aligned with a direction in which the nozzles of the liquid discharging head are arranged; a chart generating unit configured to generate a defective nozzle detection chart (C) in which lines in a sub-scanning direction corresponding to the respective nozzles of the liquid discharging head are arranged; and a position detecting unit configured to perform an interpolating process on pixel values of a plurality of pixels around a line position detected from pixel values of scanned data of the defective nozzle detection chart scanned by the scanner , and detect a position where a differential of an interpolation function derived from the interpolating process is zero, as a line position, characterized in that a length of the lines in the defective nozzle detection chart (C) is set to a length equal to or more than two periods, the two periods corresponding to a longer one of periods corresponding to frequencies of relative vibrations of the liquid discharging head, and the scanner , with respect to the conveying unit, wherein the position detecting unit uses a mean value of pixels corresponding to the length equal to or more than the two periods, in the sub-scanning direction, in a process of detecting the lines in the defective nozzle detection chart (C). a conveying unit configured to convey a recording medium (P); a liquid discharging head including nozzles arranged linearly and configured to discharge liquid onto the recording medium (P) conveyed by the conveying unit ; a scanner installed in such a manner that a main-scanning direction of the scanner is aligned with a direction in which the nozzles of the liquid discharging head are arranged; a chart generating unit configured to generate a defective nozzle detection chart (C) in which lines in a sub-scanning direction corresponding to the respective nozzles of the liquid discharging head are arranged; and a position detecting unit configured to perform an interpolating process on pixel values of a plurality of pixels around a line position detected from pixel values of scanned data of the defective nozzle detection chart scanned by the scanner , and detect a position where a differential of an interpolation function derived from the interpolating process is zero, as a line position, characterized in that a length of the lines in the defective nozzle detection chart (C) is set to a length equal to or more than two periods, the two periods corresponding to a longer one of periods corresponding to frequencies of relative vibrations of the liquid discharging head, and the scanner , with respect to the conveying unit, wherein the position detecting unit uses a mean value of pixels corresponding to the length equal to or more than the two periods, in the sub-scanning direction, in a process of detecting the lines in the defective nozzle detection chart (C). <EOS>