A blood pressure measuring apparatus which measures a blood pressure in a step of gradually changing a cuff pressure adapted to press an artery, the blood pressure measuring apparatus comprising: a pulse wave detecting unit (62, 40) which detects the cuff pressure and pulse waves of the artery; a pulse wave interval measuring unit which measures a pulse wave interval between two of the pulse waves that are successively detected; a waveform information storing unit which stores waveform information of the pulse waves, and the cuff pressure at time when the pulse waves are detected, wherein the waveform information of the pulse wave includes amplitude of the pulse wave, a time period which is required for the pulse wave to rise from a reference level to the amplitude and the pulse wave interval; a change trend calculating unit which calculates a change trend of amplitudes of the pulse waves based on a plurality of pulse wave amplitudes which are registered in the waveform information storing unit and which are used in calculating the blood pressure value; a waveform information comparing unit which compares the waveform information of two of the pulse waves that are successively detected; and a determining unit which, when two of the pulse waves, which are successively detected at different cuff pressures, satisfy predetermined conditions: that a magnitude relationship between the amplitudes of the pulse waves is consistent with the change trend; that the pulse wave interval is within a predetermined range; and that the waveform information of the pulse waves approximately coincide with each other, determines that the amplitude of latter one of the two of the pulse waves is to be used for calculating the blood pressure value. a pulse wave detecting unit (62, 40) which detects the cuff pressure and pulse waves of the artery; a pulse wave interval measuring unit which measures a pulse wave interval between two of the pulse waves that are successively detected; a waveform information storing unit which stores waveform information of the pulse waves, and the cuff pressure at time when the pulse waves are detected, wherein the waveform information of the pulse wave includes amplitude of the pulse wave, a time period which is required for the pulse wave to rise from a reference level to the amplitude and the pulse wave interval; a change trend calculating unit which calculates a change trend of amplitudes of the pulse waves based on a plurality of pulse wave amplitudes which are registered in the waveform information storing unit and which are used in calculating the blood pressure value; a waveform information comparing unit which compares the waveform information of two of the pulse waves that are successively detected; and a determining unit which, when two of the pulse waves, which are successively detected at different cuff pressures, satisfy predetermined conditions: that a magnitude relationship between the amplitudes of the pulse waves is consistent with the change trend; that the pulse wave interval is within a predetermined range; and that the waveform information of the pulse waves approximately coincide with each other, determines that the amplitude of latter one of the two of the pulse waves is to be used for calculating the blood pressure value.