Toyama became the 16th Japanese prefecture hit by the disease, the Kyodo news agency reported.
The authorities also introduced a quarantine to prevent the movement of eggs and chickens from the area around the infected farm.
Bird flu outbreaks have previously been discovered in the prefectures of Kagawa, Fukuoka, Hyogo, Miyazaki, Hiroshima, Nara, Oita, Wakayama, Okayama, Shiga, Kochi, Tokushima, Chiba, Gifu and Kagoshima. According to the Ministry for Agriculture, more than 6 million domestic birds have already been exterminated to prevent the spread of the disease.
Outbreaks of bird flu have also been recently detected in the United Kingdom, the Netherlands, northern Germany and Belgium.