Abstract: Disclosed are an apparatus and method for detecting an abnormality early. An apparatus for detecting the abnormality early includes a similar case selector configured to select similar cases associated with a monitored target from among previous case data, a data collector configured to collect status information of the monitored target, an abnormality detector configured to generate a baseline for detecting the abnormality of the monitored target from case data classified as normal among the previous case data and compare the baseline with the collected status information to detect whether the monitored target has the abnormality, and a predictor configured to, when it is detected that the monitored target has the abnormality, compare each of the selected similar cases with the collected status information to select an optimum similar case associated with the monitored target among the similar cases, and to predict a future situation development of the monitored target based on the optimum similar case.