We carried out the corrosion survey of No.2 quay wall at Etomo Harbor and-4.5m quay wall at Kitaminato Harbor, and the following results were obtained: Both corrosion rates of outward and inward sheet piles with respect to shore from H.W.L to mud zone were 0.05mm/yr or lesser, but only on convex face of outward sheet pile with respect to shore within the distance of about 30cm under the mean low water level, we observed more corrosive phenomenon and measured great corrosion rate, 0.5 to 1.0mm/yr.
　It is assumed that the above corrosion tendency depends considerably on existence of tidal range, dimesions of the depth of water and presence of fresh water, and so on.