There is no clear surrounding moats, but the west side of the tumulus is leveled nearly 10 meters wide, and the east side of the sunken rice field is considered to be the remain of a dry moat which shows the area of the tumulus.
明確な周濠は無いが古墳の西は約10メートルほどの幅で平らに整地されており、東側の一段低くなった田も墓域を示す空濠の跡と考えられている。