A user authentication method, performed by an electronic apparatus, of authenticating a user based on an utterance input, the user authentication method comprising: obtaining (S201) an input audio signal based on the utterance input of the user; obtaining (S202), from the input audio signal, at least one audio signal of an utterance section, the method characterized by : obtaining (S202), from the input audio signal, at least one audio signal of a non-utterance section; generating (S203) environment information indicating an environment in which the utterance input is received, based on the at least one audio signal of the non-utterance section; obtaining a result of a comparison between the generated environment information and registration environment information indicating an environment in which a registration utterance input corresponding to a previously registered registration audio signal of the user is received; adjusting (S204) an authentication criterion for authenticating the user based on the result of the comparison; and authenticating (S205) the user based on the adjusted authentication criterion and the input audio signal, wherein the environment information comprises information related to noise around the electronic device, information about a location of the electronic apparatus and a distance between the electronic device and the user. obtaining (S201) an input audio signal based on the utterance input of the user; obtaining (S202), from the input audio signal, at least one audio signal of an utterance section, the method characterized by : obtaining (S202), from the input audio signal, at least one audio signal of a non-utterance section; generating (S203) environment information indicating an environment in which the utterance input is received, based on the at least one audio signal of the non-utterance section; obtaining a result of a comparison between the generated environment information and registration environment information indicating an environment in which a registration utterance input corresponding to a previously registered registration audio signal of the user is received; adjusting (S204) an authentication criterion for authenticating the user based on the result of the comparison; and authenticating (S205) the user based on the adjusted authentication criterion and the input audio signal, wherein the environment information comprises information related to noise around the electronic device, information about a location of the electronic apparatus and a distance between the electronic device and the user. obtaining (S202), from the input audio signal, at least one audio signal of a non-utterance section; generating (S203) environment information indicating an environment in which the utterance input is received, based on the at least one audio signal of the non-utterance section; obtaining a result of a comparison between the generated environment information and registration environment information indicating an environment in which a registration utterance input corresponding to a previously registered registration audio signal of the user is received; adjusting (S204) an authentication criterion for authenticating the user based on the result of the comparison; and authenticating (S205) the user based on the adjusted authentication criterion and the input audio signal, wherein the environment information comprises information related to noise around the electronic device, information about a location of the electronic apparatus and a distance between the electronic device and the user. <EOS>