Patent ID: 8777866

Claim:
A pulse rate counting device, comprising: a short-term average value calculation unit receiving input of pulse wave data acquired from a change of bloodstream and calculating an average interval of predetermined previous pulses; a fluctuation value calculation unit calculating a fluctuation value that is an average of absolute values of differences between the average interval and a predetermined number of previous actual pulse wave intervals; a search range determination unit calculating a width of a search range of a detection point as a reference of a next pulse wave interval by multiplying a previous pulse wave interval by the fluctuation value, calculating an amount of displacement on a basis of a time change of the average interval, and determining as a search range a range including an appearance prediction value of a next detection point calculated from the average interval and indicated by the width of a search range from a starting point that is a sum of the amount of displacement and the appearance prediction value; and a pulse wave interval detection unit detecting the detection point in the determined search range, and outputting an interval between a predetermined detection point and a current detection point as a pulse wave interval.