To provide a non-invasive blood pressure estimation apparatus, which can accurately estimate systolic blood pressure from blood flow sound of a dialysis patient and continuously estimate systolic blood pressure by continuously picking up the blood flow sound. A blood pressure estimation apparatus creates a standard pulse curve by relating a start point and end point of a rising phase of a pulse wave to diastolic blood pressure and systolic blood pressure, respectively, creates a correspondence curve between blood flow sound power and estimated blood pressure by contrasting the standard pulse curve with the blood flow sound power curve obtained from blood flow sound at a shut site, with the two curves plotted on the same time axis, derives a systolic blood pressure estimation linear function from the correspondence curve, inputs a measured maximum value of the blood flow sound power into the linear function, and thereby estimates systolic blood pressure.