A lesion diagnosis apparatus and method for diagnosing images in real time to notify a user that a lesion is detected and providing the user with information about the detected lesion, thereby enhancing accuracy and convenience in a diagnosis. The lesion diagnosis apparatus includes a diagnoser configured to diagnose lesions in images received from a probe; and a guide information provider configured to notify a user that a lesion is detected and to provide guide information, when the lesion is detected.