To determine the emotion of a viewer more accurately by measuring the pupil diameter while eliminating the influence of brightness, breathing, and pulse. A reference data measuring unit measures, as reference data, a reference pupil diameter Csk, a breathing influenced pupil diameter Dskt, and a pulse influenced pupil diameter Eskt for each of various combinations of the brightness of an entire screen and the brightness of a visual point. A measuring unit identifies the reference pupil diameter Csk, the breathing influenced pupil diameter Dskt, and the pulse influenced pupil diameter Eskt corresponding to the elapsed time of content. The measuring unit sets a pupil diameter Bt as an attentive pupil diameter A1t in the case of two or more breathing times (T1), calculates the attentive pupil diameter A1t by subtracting the breathing pupil diameter Dskt from the pupil diameter Bt in the case of two or more pulse times and less than two breathing times (T2), and calculates the attentive pupil diameter A1t by further subtracting the pulse influenced pupil diameter Eskt therefrom in the case of less than two pulse times (T3). The measuring unit calculates an attention-attributable pupil diameter A2t by subtracting the reference pupil diameter Csk from the attentive pupil diameter A1t, and divides the attentive pupil diameter A1t and the attention-attributable pupil diameter A2t by the reference pupil diameter Csk to calculate the degrees of attention P1t and P2t.
