A blood pressure measurement device according to one aspect includes: a blood pressure measurement unit configured to measure blood pressure at a measurement target site of a measurement target subject; a pulse transit time measurement unit configured to measure a pulse transit time at the measurement target site of the measurement target subject; a blood pressure value calculation unit configured to calculate a blood pressure value, on the basis of measurement results of the pulse transit time and a relational expression representing a correlation between the pulse transit time and the blood pressure; a posture instruction unit configured to instruct the measurement target subject to assume a plurality of postures in which height positions of the measurement target site with respect to a heart of the measurement target subject are different from each other; and a calibration unit configured to calibrate the relational expression, on the basis of the blood pressure measured by the blood pressure measurement unit and the pulse transit time measured by the pulse transit time measurement unit, for each of the plurality of postures.