An image acquisition unit acquires images from a plurality of cameras arranged so as to be spaced apart by a predetermined distance such that the optical axes are not substantially coaxial with each other a plurality of light sources are each arranged such that the optical axis is substantially coaxial with either of the plurality of cameras and as first image acquisition regarding detection light supplied from a first light source that is one of the plurality of light sources, an image for extracting a bright pupil image is acquired using a camera that is substantially coaxial with the first light source, and an image for extracting a dark pupil image is acquired using a camera that is not substantially coaxial with the first light source.
