BLOOD PRESSURE INFORMATION CALCULATING DEVICE, BLOOD PRESSURE INFORMATION CALCULATING METHOD, BLOOD PRESSURE INFORMATION CALCULATING PROGRAM, AND RECORDING MEDIUM FOR RECORDING SAID PROGRAM

A blood pressure information calculating device includes an input unit to which a waveform based on a pulse wave of the subject and reference blood pressure information serving as a reference for calculating the blood pressure information on the basis of the waveform based on the pulse wave are input, a conversion unit that calculates a phase spectrum of a waveform based on the pulse wave by performing Fourier transformation on the waveform based on the pulse wave, a calculation unit that calculates a correction value using at least one of a phase of a main wave corresponding to a pulse of the subject and a phase of a second harmonic wave of the main wave on the basis of the phase spectrum, and a calculation unit that calculates an average blood pressure by correcting the reference blood pressure information using the correction value.