A liquid discharging apparatus comprising: a conveying unit configured to convey a recording medium; a liquid discharging head (220C,220M,220Y,220K) including nozzles arranged linearly and configured to discharge liquid onto the recording medium conveyed by the conveying unit; a scanner (231,232) installed in such a manner that a main-scanning direction of the scanner (231,232) 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 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 (231,232), 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 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 (231,232), 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. a conveying unit configured to convey a recording medium; a liquid discharging head (220C,220M,220Y,220K) including nozzles arranged linearly and configured to discharge liquid onto the recording medium conveyed by the conveying unit; a scanner (231,232) installed in such a manner that a main-scanning direction of the scanner (231,232) 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 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 (231,232), 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 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 (231,232), 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.