An apparatus and a method predict an upcoming stage of carotid stenosis. The apparatus includes a receiving unit, a cluster determining unit, a risk factor score extracting unit, a prediction model storage unit, and a predicting unit. The method includes receiving a patient's medical test data relating to carotid stenosis; determining a cluster to which the patient's medical test data belong based on a gender of the patient; extracting from the patient's medical test data a risk factor score comprising a result of carotid stenosis ultrasonography; storing a plurality of prediction models used to predict an upcoming stage of carotid stenosis; and obtaining an outcome by applying a value indicating a stage of carotid stenosis corresponding to the result of carotid stenosis ultrasonography and the extracted risk factor score to the prediction model corresponding to the determined cluster among the plurality of prediction models.