A failure detection device configured to detect a failure of a sound generating device outputting a sound through a speaker based on sound data, wherein the failure detection device comprises: an electronic watermark signal generating means configured to generate an electronic watermark signal including collation data used for collation of whether or not a failure of the sound generating device is detected, wherein the electronic watermark signal generating means is configured to generate the electronic watermark signal by spreading the collation data with a spread code which is generated at random; an addition means configured to add the electronic watermark signal to the sound data output by the sound generating device to generate a stego-signal; the speaker configured to output the stego signal as a sound; a microphone configured to collect the sound output from the speaker ; a collation data detection means configured to detect the collation data from the stego-signal, by reversely spreading the stego-signal with the spread code used for generating the electronic watermark signal; a failure determination means configured to determine presence or absence of the failure of the sound generating device , by collating the collation data detected by the collation data detection means , with the collation data included in the electronic watermark signal by the electronic watermark signal generating means ; and a second failure detection device configured to electrically detect a failure of the speaker , wherein the failure determination means is further configured to determine presence or absence of a failure of the speaker and the sound generating device , by combining a determination result of the second failure detection device with a determination result of the failure of the sound generating device . an electronic watermark signal generating means configured to generate an electronic watermark signal including collation data used for collation of whether or not a failure of the sound generating device is detected, wherein the electronic watermark signal generating means is configured to generate the electronic watermark signal by spreading the collation data with a spread code which is generated at random; an addition means configured to add the electronic watermark signal to the sound data output by the sound generating device to generate a stego-signal; the speaker configured to output the stego signal as a sound; a microphone configured to collect the sound output from the speaker ; a collation data detection means configured to detect the collation data from the stego-signal, by reversely spreading the stego-signal with the spread code used for generating the electronic watermark signal; a failure determination means configured to determine presence or absence of the failure of the sound generating device , by collating the collation data detected by the collation data detection means , with the collation data included in the electronic watermark signal by the electronic watermark signal generating means ; and a second failure detection device configured to electrically detect a failure of the speaker , wherein the failure determination means is further configured to determine presence or absence of a failure of the speaker and the sound generating device , by combining a determination result of the second failure detection device with a determination result of the failure of the sound generating device . <EOS>