In an ultrasound blood pressure monitor, a blood pressure diameter measurement section measures blood pressure diameter of a radial artery which is a measurement target based on reception results of ultrasound from an ultrasound sensor. In addition, a pressurizing section adds a pressure from a body surface so that the radial artery is pressed. Then, a correlation formula, which expresses a relationship between blood vessel diameter and blood pressure of the radial artery under pressurization by the pressurizing section, is found and stored in a storage section. Then, a blood pressure calculation section calculates blood pressure using the blood vessel diameter which is measured under pressurization and storage data in the storage section by controlling the pressurization operation of the pressurizing section.
