Saji Observatory, Astronomical observatory in Tottori Prefecture, Japan

Saji Observatory is an astronomical facility in the Saji district of Tottori, Tottori Prefecture, opened in July 1994. Its main instrument is a 103 cm reflecting telescope, the largest in Japan when the facility opened, housed in the observatory building. The site also includes a planetarium, exhibition rooms, a multipurpose house, a rest house and overnight lodging in four Hoshi no Cottage units and the Cosmos Hall.

Saji Astro Park opened in July 1994 in Saji, now part of Tottori, with Kiyoki Kōzai, retired from the National Astronomical Observatory of Japan, as director and astronomer Shin Oyama as park head. Its 103 cm reflecting telescope was Japan's largest public telescope at opening. The observatory has discovered 22 numbered asteroids, proposing names for 17 of them.

The observatory serves as a gathering place where people interested in astronomy come together for regular stargazing events and educational programs. These occasions connect locals and visitors through their shared curiosity about the night sky.

Opening hours run 9:00–22:00 from April to September and 9:00–21:00 from October to March. The observatory closes on Mondays and the third Tuesday of each month, moved to the following day when these fall on holidays, and also over the New Year period. It stands at 1071-1 Takayama, Saji, Tottori; by car take National Route 482 from the Mochigase interchange toward Maniwa and Saji.

The observatory has discovered 22 numbered asteroids, and it proposed names for 17 of them. These include "Saji", "Tottori" landmarks such as "Daisakyu", and people like photographer Shoji Ueda, whose naming was suggested with advice from his student Masaharu Fukuyama, and honorary director Keizo Saji.