PROBLEM TO BE SOLVED: To shorten processing time required for iris authentication in one embodiment.SOLUTION: An iris authentication device comprises an adjustment unit and an indication unit. The adjustment unit adjusts imaging conditions of an imaging device using a second image obtained by converting a first image imaged by the imaging device so as to have lower resolution. The indication unit causes a secure processor operating in a secure environment to compare an iris digital template including data for characterizing an individual iris with a third image imaged by the imaging device under the imaging conditions adjusted by the adjustment unit.SELECTED DRAWING: Figure 5
