A device for measuring a characteristic reading distance of an individual, includes a measurement support carrying at least one ultrasound emitter member and at least one ultrasound receiver member, at least one of these members, referred to as a main measurement member, possessing a measurement axis on which emission or reception by the main measurement member is privileged, and being suitable for emitting or receiving ultrasound propagating in a measurement cone centered on its measurement axis. The device further includes an electronic processor unit adapted, as a function of the ultrasound signal received by the receiver member, to deliver a signal representative of the distance between the measurement support and an eyeglass frame worn by the individual's head, and to deduce therefrom the characteristic reading distance, and elements to verify that the eyeglass frame is situated at least in part in the measurement cone of the main measurement member.
