An electronic sphygmomanometer having a function to calculate an index value of risk of circulatory system disease from measured blood pressure information includes a CPU, a memory, and a display. The CPU calculates the blood pressure of a person being examined based on pressure changes of an air bladder as measured by a pressure sensor. The memory stores data of the measured blood pressure together with time information of the measurement. The CPU calculates an index value of risk of circulatory system disease of the person being examined based on a difference between a blood pressure value obtained from a measurement and a blood pressure value obtained from a previous measurement and an elapsed time between the measurement and the previous measurement, A display part displays the calculated index value of risk of circulatory system disease of the person being examined together with the measured blood pressure.
