An endoscope reprocessor includes: an endoscope housing portion a medicinal solution tank in which a medicinal solution is stored a medicinal solution transfer portion that transfers the medicinal solution from the medicinal solution tank to the endoscope housing portion a comparison portion that compares the concentration of the medicinal solution and a first reference concentration a first adjustment portion that increases a reaction rate of the medicinal solution in a state in which the concentration of the medicinal solution is lower than the first reference concentration and a control portion to which the comparison portion and the first adjustment portion are connected, and which drives the first adjustment portion in a case where the comparison portion determines that the concentration of the medicinal solution is lower than the first reference concentration.
