1. An apparatus for evaluating a degree of recovery of a living subject from a surgical operation which the subject has undergone, the apparatus comprising: a circulatory-organ-relating-information obtaining means for iteratively obtaining, after the operation, a piece of circulatory-organ-relating information relating to a circulatory organ of the subject; and a recovery-degree evaluating means for evaluating the degree of recovery of the subject, based on at least one piece of circulatory-organ-relating information obtained by the circulatory-organ-relating-information obtaining means.