A method of calculating a blood pressure, includes: providing a non-invasive blood pressure measurement apparatus which includes a cuff being inflatable and deflatable and adapted to be fitted on a part of a living body and in which a plurality of calculation methods each of which has priority in accordance with a type of noise information are set; detecting, by the cuff, a signal waveform representing a change in an oscillation amplitude and a change in a cuff pressure; determining the type of the noise information contained in the detected signal waveform; deciding the blood pressure from at least one candidate value for the blood pressure, which is calculated by one of the calculation methods that has the priority with respect to the determined type of the noise information; and displaying the decided blood pressure.