In a clinical laboratory, the degree of contamination of an automatic analyzer may constantly change due, for instance, to the operation of the automatic analyzer and newly added examinations, and there is a risk of failure to adequately maintain the performance of the automatic analyzer by performing calibration at conventional intervals. Meanwhile, the result of quality control varies depending on the performance of an unsealed reagent. Hence, performing calibration at predetermined intervals may fail to flexibly calibrate the reagent when the performance of the reagent is changed by reagent replenishment or by contamination. Provided is a quality control method for issuing a warning to indicate an optimum calibration method and calibration intervals in accordance with the contents of a quality control screen and with the pattern of variation in the result of calibration.