The Hōsa Library (蓬左文庫) is a library located on the compound of the Ōzone Shimoyashiki in Nagoya, central Japan.
It was established by Tokugawa Yoshinao, the first lord of the Owari Domain, as an official archive. It was transferred from the Tokugawa family to Nagoya City in 1950. Presently the library has about 110,000 items including classic literature.
The library cooperates closely with the neighbouring Tokugawa Art Museum and the Tokugawa Garden.