In order to establish an objective method for evaluating emotions, we sought to identify the physiological parameters that change in response to various unpleasant emotions. Experiments and analysis were conducted using video stimuli that evoked the unpleasant emotions of “fear” (high arousal), “disgust” (medium arousal), and “sadness” (low arousal), as well as the pleasant emotion “exhilaration” (high arousal). The results of our questionnaire confirmed that the emotions evoked by each stimulus were valid. Because the physiological response of the autonomic nervous system differs depending on the arousal level of each emotion evoked, analysis of general physiological responses did not reveal any physiological values common to unpleasant emotions with different arousal levels. “Fear” and “exhilaration,” which have high arousal levels, showed similar physiological responses, while “disgust” and “sadness,” which have different arousal levels, responded with different physiological quantities. Furthermore, there was no commonality in the physiological responses to unpleasant stimuli. On the other hand, analysis using blood pressure waves showed that a physiological index linking two parameters that tend to change in common to the three unpleasant emotions increased in common to the three unpleasant emotions.