1. A method of measuring a pupil distance, comprising: locating an imaging device at a position a predetermined distance away from a member attached to eyeglasses worn by a subject, the member having two indicators; photographing the subject while the subject observes an observing point in the vicinity of the imaging device; measuring an apparent distance between left and right pupils of the subject on a photographed image; and obtaining an interpupillary distance PD in accordance with: 
 PD =[( A+B )× C×E ]/( A×D )   (1) where “A” represents a distance between the member and the imaging device, “B” represents a distance between a center of rotation of each eye of the subject and the member, “C” represents an actual distance between the indicators in a direction parallel with a line connecting left and right centers of rotation of the subject, “D” represents an apparent distance between the indicators in the direction parallel with the line connecting the left and right centers of rotation on the photographed image, and “E” represents the apparent distance between the left and right pupils of the subject on the photographed image.