It was constructed in the end of Kofun period (from the end of sixth century to the early seventh century) and has been known of the horizontal stone chamber using beautifully arranged gigantic stones, which is called Iwayayama-kofun Tumulus.
古墳時代終末期（6世紀末から7世紀前半）の築造で、岩屋山古墳といわれる整美な巨石を用いた横穴式石室で知られる。