In a sphygmomanometer for measuring blood pressure according to a volume compensation method, an upper arm V0 equivalent cuff pressure representing a cuff pressure in a state where an inner pressure and an outer pressure of an artery of an upper arm are in equilibrium is specified based on a cuff pressure signal of the upper arm. For example, the upper arm V0 equivalent cuff pressure is detected as an average blood pressure obtained from the cuff pressure signal of the upper arm. After a control target value and an initial cuff pressure in the volume compensation are detected, a difference between the initial cuff pressure and the upper arm V0 equivalent cuff pressure is calculated as a correction value, and the blood pressure value in the volume compensation method is corrected with the calculated correction value.