The objective of the present invention is to provide an emotion estimating device capable of estimating emotions more reliably and more stably. The present invention relates to an emotion estimating device which: acquires a brain potential signal of a subject； acquires a facial image of the subject； acquires a pupillary diameter of the subject； acquires information relating to the brightness of an object being viewed by the subject； calculates a degree of attention representing the pupillary diameter from which the effect of the brightness of the object being viewed has been eliminated, on the basis of the acquired pupillary diameter, the acquired brightness information, and a correspondence relationship between the brightness information and the pupillary diameter of the subject, acquired in advance； calculates a facial image feature quantity representing a degree of change of expression, on the basis of amounts of displacement of the locations of certain sites in the acquired facial image compared with the locations of the certain sites in a normal condition, set in advance； calculates brain potential data on the basis of specific frequency bands attributable to brain activity, extracted from the acquired brain potential signal； and estimates an emotion of the subject on the basis of the calculated degree of attention, facial image feature quantity, and brain potential data.L'invention a pour objet de fournir un dispositif d'estimation d'émotion susceptible d'estimer des émotions de manière plus fiable et plus stable. L'invention concerne un dispositif d'estimation d'émotion qui : acquiert un signal de potentiel cérébral d'un sujet； acquiert une image faciale du sujet； acquiert un diamètre pupillaire du sujet； acquiert des informations relatives à la luminosité d'un objet vu par le sujet； calcule un degré d'attention représentant le diamètre pupillaire duquel l'effet de la luminosité de l'objet visualisé a été éliminé, sur la base du diamètre pupillaire acquis, de
