An eye gaze detection supporting device includes an illuminator including a light source that performs irradiation with light, a plurality of imaging units, position detectors that detect a first position indicating a center of a pupil and a second position indicating a center of corneal reflection, from an image of an eye ball of a subject irradiated with light by the illuminator, and captured by the imaging units, and a calculator that calculates a fourth position indicating a curvature center of a cornea, based on a position of the light source, a third position on a display, the first position, and the second position.