A blood pressure measurement device includes a cuff, a display, a distance sensor, an acceleration sensor, and a CPU. The display displays a positional relationship between the patients heart and the device, which includes a flat screen. The distance sensor measures a distance between the device and the patient, and detects a subject to be measured on a line perpendicular to the flat screen of the display and measures the distance. The acceleration sensor measures an angle of inclination of the device when mounted on the patients wrist. The CPU calculates a positional relationship between the patients heart and the device based on the distance between the device and the subject to be measured, the angle of inclination of the device mounted on the patients wrist, the length of the patients forearm and upper arm, and a vertical distance between the patients shoulder and heart.
