The endoscope reprocessor 1 includes a concentration measurement chamber 91, a stock solution supply unit 94, a diluent supply unit 95, a holding unit 96 that holds the concentration sensor 97, a calibration curve storage unit 104, Based on the first point R1 associated with the sensor output value of the diluted working liquid and the second output R2 and the sensor output value at the time of measuring the concentration of the working liquid after dilution, A calculating unit 106 for calculating a degree of divergence between the calibration curve Ls and the virtual calibration curve Lc a determining unit 107 for determining whether the virtual calibration curve is valid or invalid based on the divergence degree .内視鏡リプロセッサ1は、濃度測定室91と、原液供給部94と、希釈液供給部95と、濃度センサ97を保持する保持部96と、検量線記憶部104と、原液の濃度測定時のセンサ出力値および第1濃度を対応付けた第1点R1と、希釈後の実用液の濃度測定時のセンサ出力値および第2濃度を対応付けた第2点R2と、に基づいて、仮想検量線Lcの情報を作成する検量線作成部と、検量線Lsと仮想検量線Lcとの乖離度を算出する算出部106と、乖離度から仮想検量線の有効/無効を判定する判定部107と、を含む。
