The server device (10) acquires an image in which a subject is photographed, and, of a plurality of wavelength component signals included in the image, a section overlapping with a frequency band that can be taken by a pulse wave is equal to or shorter than a predetermined length. The intensity representing the signal component in the specific frequency band is extracted for each wavelength component. Furthermore, the server device (10) is a weighting coefficient that is multiplied to the signal when the signal is calculated between the wavelength components using the intensity extracted for each wavelength component, and is multiplied by the specific frequency band after the multiplication. A weighting coefficient that minimizes the calculated value of the signal component is calculated. Further, the server device (10) multiplies at least one signal component among the signals of each wavelength component by a weighting factor, calculates a signal between the wavelength components after multiplication by the weighting factor, and uses the signal after the calculation. To detect the pulse wave of the subject.サーバ装置（１０）は、被験者が撮影された画像を取得し、画像に含まれる複数の波長成分の信号のうち、脈波が採り得る周波数帯との間で重複する区間が所定長以下である特定周波数帯の信号成分を代表する強度を波長成分ごとに抽出する。さらに、サーバ装置（１０）は、波長成分ごとに抽出された強度を用いて、各波長成分の間で信号が演算される場合に信号へ乗算される重み係数であって乗算後に特定周波数帯の信号成分の演算値が最小化される重み係数を算出する。さらに、サーバ装置（１０）は、各波長成分の信号のうち少なくとも一方の信号成分に重み係数を乗算し、重み係数の乗算後に各波長成分の間で信号を演算し、演算後の信号を用いて被験者の脈波を検出する。
