An endoscope reprocessing method includes: cleaning, disinfecting, or sterilizing an inside of a pipe line and an outer surface of an endoscope accommodated in a treatment tank； rinsing the outer surface of the endoscope with a rinsing liquid while filling the inside of the pipe line of the endoscope with gas； collecting a first sample from the rinsing liquid used for rinsing the outer surface of the endoscope； rinsing the inside of the pipe line of the endoscope with the rinsing liquid； and collecting a second sample from the rinsing liquid used for rinsing the inside of the pipe line of the endoscope.
