An information processing device performs: acquiring a face similarity indicating a similarity between a face of a first person and a face of a second person; acquiring a voice similarity indicating a similarity between a voice of the first person and a voice of the second person; calculating an integrated similarity by integrating the face similarity and the voice similarity, and determining the integrated similarity as a final similarity when the face similarity falls within an integrated range including a threshold which is used to determine whether the first person and the second person are identical to each other, and calculating the face similarity as a final similarity when the face similarity is out of the integrated range; and outputting the final similarity.