To provide an electronic sphygmomanometer capable of accurately obtaining a circumferential length of a measurement site without providing a complicated mechanism of a cuff band or pressurizing means for the cuff band. The electronic sphygmomanometer includes a cuff band (20) wrapped around a measurement site a fluid bag (201) internally included in the cuff band (20) pressurizing means (102, 111) for pressurising an inside of the fluid bag (201) an electric depressurizing valve (103) for depressurizing an inside of the fluid bag (201) an electric depressurizing valve drive circuit (112) for regulating a drive energy amount of the electric depressurizing valve (103) and circumferential length estimating means (124) for obtaining a circumferential length of the measurement site by using a drive energy amount regulated by the electric depressurizing valve drive circuit (112) and previously set basic data.
