Provided is technology that makes it possible to measure visual behavior with respect to objects that are at different distances in the depth direction, while reducing burden on a subject. A method for measuring visual behavior of a subject to design an eyeglass lens includes: a step (a) of ascertaining a head rotation amount that is generated by the subject in a sagittal plane of the subject when gazing at each of a plurality of gaze points that are set at predetermined distances different from each other in a forward depth direction; and a step (b) of determining an eyeball rotation amount that is generated by the subject when gazing at each of the plurality of gaze points, based on the head rotation amount.