A blood pressure measurement unit (6) measures the blood pressure and a CPU (5) accordingly stores, in a blood pressure storage unit (7), measurement data as well as time information regarding the time at which the blood pressure is measured. The CPU (5) calculates, as representative measurement data, the average of a plurality of measurement data stored in the blood pressure storage unit (7) and correlated with the time information indicating a time in the range between nine weeks ago and ten weeks ago, correlates the representative measurement data with time information representing the corresponding week and stores the data with the time information in the blood pressure storage unit (7). At this time, the CPU (5) deletes from the blood pressure storage unit (7) those measurement data based on which the representative measurement data is calculated.
