A blood-pressure estimating apparatus, including a pulse-wave detecting device which detects a pulse wave from a portion of a living subject, a blood-pressure measuring device which includes an inflatable cuff adapted to be worn on the portion of the subject and measures, with the cuff, a diastolic blood pressure and a systolic blood pressure of the portion of the subject, and a mean-blood-pressure estimating device which converts, based on a minimum magnitude and a maximum magnitude of the pulse wave detected by the pulse-wave detecting device and the diastolic and systolic blood pressure measured by the blood-pressure measuring device, a magnitude of a gravity center of an area defined by the pulse wave into an estimated mean blood pressure of the portion of the subject.