Patent ID: 7232412

Claim:
A blood pressure measuring apparatus comprising: oppressing means for oppressing blood vessels of a human body; oppressing pressure detecting means for detecting the oppressing pressure value on the blood vessels by the oppressing means; similar waveform detecting means for detecting similar waveforms changing similarly to pressure changes in the blood vessels oppressed by the oppressing means in one heartbeat period; and blood pressure calculating means for determining the scale of the similar waveforms detected by the similar waveform detecting means, and calculating the blood pressure by matching the determined scale of similar waveforms with the scale of waveforms showing pressure changes in the blood vessels, wherein the blood pressure calculating means includes: level detecting means for detecting the level of the similar waveforms in one heartbeat period; and means for determining the scale of the similar waveforms on the basis of the similarity ratio indicated by the ratio of the difference of levels at two moments of maximum level and minimum level detected by the level detecting means and the difference of the oppressing pressure values detected by the oppressing pressure detecting means corresponding to the two moments, and matching the determined scale of similar waveforms with the scale of the waveforms showing pressure changes in the blood vessels.