It is thought that the tumulus was constructed in the early Kofun period (tumulus period) (the fourth century), that is to say, it was the one of the oldest in Somanouchi-kofun Tumulus Cluster that the tumulus belongs to.
築造時期は古墳時代前期（4世紀）と見られており、同古墳が属する杣之内古墳群の中でも最も古い時期に造られた古墳である。