A bend information computation apparatus (10) is to compute bend information representing a direction of bend and a magnitude of bend of a detection target group (410) provided on a light guide (420). The detection target group includes a plurality of detection targets disposed at an identical position along a length of the light guide. Each of the detection targets modulates the intensity of light guided by the light guide in accordance with the direction of bend and the magnitude of bend. The bend information computation apparatus includes an input unit (190) to be input detected light quantity information of light of a wavelength corresponding to each of the detection targets, a storage (130) to store a bend coefficient and intensity modulation information of each of the detection targets, and a light quantity information relationship representing a relationship between the bend coefficient and intensity modulation information and the detected light quantity information, a first arithmetic operator (212) to calculate light quantity variation information of each of the detection targets, based on the detected light quantity information and the light quantity information relationship, and a second arithmetic operator (214) to calculate the bend information of the detection target group, based on the light quantity variation information and the bend coefficient.