To provide an arrangement for detecting a pulse wave which can measure a more exact pulse rate even when a processing means having a low calculation potential is used.

An A/D conversion circuit 106 samples at 16Hz the pulse wave detected by a pulse wave sensor 101, carries out A/D conversion, and outputs the converted pulse wave to an irregular running average treatment circuit 107 in order. The irregular running average treatment circuit 107 outputs as two of an 8Hz signal on an average at a time in order without overlapping a signal from an A/D conversion circuit 106, and an FFT (fast Fourier transformation) conversion circuit 108 carries out the Fourier transform of the averaged signal. An A/D conversion circuit 111 samples locomotor noise detected by an acceleration sensor 109 at 8Hz, carries out the A/D conversion, and outputs the unvested noise to an FFT conversion circuit 112 in order, and the FFT conversion circuit 112 carries out the Fourier transform of the input signal. A pulse rate arithmetic circuit 113 computes the pulse rate by taking a difference in the output signals between the FFT conversion circuits 108 and 112. The pulse rate is displayed on a displaying portion 114.