A method of determining a dog's emotions from its voice with objective supports. The invention follows the procedures of converting dog's voices into electrical audio signals, extracting characteristics in a time to frequency component relation map of the audio signals as a input voice pattern, storing in advance in memory reference voice patterns for various emotions that respectively represent characteristics of time to frequency component relation maps, comparing the input voice pattern with the reference voice patterns, and determining what a dog feels by declaring emotion of the particular reference voice pattern showing the highest correlation with the input voice pattern as a result of the comparison, and emotions represented by the reference voice patterns include “loneliness”, “frustration”, “aggressiveness”, “assertiveness”, “happiness”, and “wistfulness”, and hence, the present invention attains an effective way of determining dog's emotions with objective supports.