A blood pressure measuring apparatus comprising: a cuff configured to be mounted to a region of a living body in which a vein and an artery exist; a pressure control unit configured to control an applied pressure applied to the region by the cuff mounted to the region; a detection unit configured to detect pressure waveforms in which pulse wave components from the region overlap with the applied pressure; and an analysis unit configured to obtain an arterial pressure, a respiratory variation on the waveform of artery and a venous pressure based on the pressure waveforms detected by the detection unit through one-time blood pressure measurement, wherein the analysis unit is configured to obtain: the respiratory variation on the waveform of artery based on data of a first pressure waveform of the pressure waveforms in a first process, in which the applied pressure is kept at a constant pressure by the pressure control unit ; the venous pressure based on data of a second pressure waveform of the pressure waveforms in a second process in which the applied pressure is decreased or increased by the pressure control unit; and the arterial pressure based on data of a third pressure waveform of the pressure waveforms in a third process in which the applied pressure is decreased or increased by the pressure control unit , and wherein the first, second and third processes for obtaining respectively the respiratory variation, the venous pressure, and the arterial pressure are completed in about 140 seconds. a cuff configured to be mounted to a region of a living body in which a vein and an artery exist; a pressure control unit configured to control an applied pressure applied to the region by the cuff mounted to the region; a detection unit configured to detect pressure waveforms in which pulse wave components from the region overlap with the applied pressure; and an analysis unit configured to obtain an arterial pressure, a respiratory variation on the waveform of artery and a venous pressure based on the pressure waveforms detected by the detection unit through one-time blood pressure measurement, wherein the analysis unit is configured to obtain: the respiratory variation on the waveform of artery based on data of a first pressure waveform of the pressure waveforms in a first process, in which the applied pressure is kept at a constant pressure by the pressure control unit ; the venous pressure based on data of a second pressure waveform of the pressure waveforms in a second process in which the applied pressure is decreased or increased by the pressure control unit; and the arterial pressure based on data of a third pressure waveform of the pressure waveforms in a third process in which the applied pressure is decreased or increased by the pressure control unit , and the respiratory variation on the waveform of artery based on data of a first pressure waveform of the pressure waveforms in a first process, in which the applied pressure is kept at a constant pressure by the pressure control unit ; the venous pressure based on data of a second pressure waveform of the pressure waveforms in a second process in which the applied pressure is decreased or increased by the pressure control unit; and the arterial pressure based on data of a third pressure waveform of the pressure waveforms in a third process in which the applied pressure is decreased or increased by the pressure control unit , and wherein the first, second and third processes for obtaining respectively the respiratory variation, the venous pressure, and the arterial pressure are completed in about 140 seconds. <EOS>