Disclosed is a pupil detection device capable improving the pupil detection accuracy even if a detection target image is a low-resolution image. In a pupil detection device (100), an eye area actual size calculation unit (102) acquires an actual scale value of an eye area, a pupil state prediction unit (103) calculates an actual scale prediction value of a pupil diameter, a necessary resolution estimation unit (105) calculates a target value of resolution on the basis of the calculated actual scale prediction value, an eye area image normalization unit (107) calculates a scale-up/scale-down factor on the basis of the calculated target value of resolution and the actual scale value of the eye area, and normalizes the image of the eye area on the basis of the calculated scale-up/scale-down factor, and a pupil detection unit (108) detects a pupil image from the normalized eye area image.
