PURPOSE: To adjust an inter-lens interval in accordance with the nose of each person by executing engagement between a spring bridge and lenses by means of specified configuration.

CONSTITUTION: The respective end parts of the spring bridge 24 are attached to the upper part of the respective lenses, a groove 32 is provided in the upper parts on the inner surface 16 of the lens 12, the other groove 34 is provided by opposing the groove and a series of notches 36 are provided on the upper side end surface 20 of the lens 12. Therefore, when the spring bridge 24 is pulled or pushed in a longitudinal direction on the lens, the legs of the spring bridge 24 are slid in the groove of the lens and distance between the two lenses is changed. In this case, a return stop is slid on the notche 36 on the upper side end surface of the lens and engaged with another notch and the both lenses are held at desired interval by the engagement. Thus, the interval of the lenses is adjusted so as to fit the nose of each person.