To precisely and simply read a retina pattern when authenticating an individual by the retina pattern in a portable radio terminal.

This portable radio terminal is provided with a retina pattern authentication system for analyzing the retina pattern shot by a CCD camera 3 and conducting authentication. The retina pattern authentication system has a sighting determining means for determining whether the eyeball during being shot by the CCD camera 3 matches a prescribed sighting position or not, and takes in the retina pattern to analyze when the eyeball matches the prescribed sighting position. The sighting determining means determines whether the eyeball matches the prescribed sighting position or not from the pupil.