1. A diagnosis supporting device comprising: an imaging unit that images a subject; an eye gaze detector that detects an eye gaze direction of the subject from an image imaged by the imaging unit; a gaze point detector that detects a gaze point of the subject in a display area of a display on the basis of the eye gaze direction; and an output controller that causes the display area to display a diagnostic image composed by superposing a pattern image onto a natural image.