In Toppusi-Wakasato fishery port lying at Lake Saroma in Hokkaido, the fishery infrastructures have been often built on a soft ground. This situation induced asevere problem of deforming in quay structure including steel sheet-pile. The present study allowed to fully understand the cause of deformation. To take measures to meet this situation, double sheet-pile pier have been designed and constructed. For this investigation, we refer to effect of double sheet-pile pierbased on the analysis FEM model.