The present paper relates to the hydraulic model experiments for the construction of artificial beach of the Ugusu Coast which is naturally composed of coarse materials because of steep bathymetry in the offshore and seasonal rough climate.
　The ordinary detached breakwaters to preserve artificial beach materials will hamper the view of sea bathers because the openings between the neighboruing detached breakwaters must be narrowed under such a rough wave climate.
　Thus, the methods to adopt the submerged breakwaters for the protection of openings have been examined first of all so that hampering of the view may be much released by expanding the opening width owing to the submerged breakwaters: the conditions of the crown height and width of the submerged breakwaters for the efficient preservation of beach materials were obtained by two dimensional model experiments with a fixed bed. Secondly, the efficiency of the obtained dimensions of the crown height and width in protecting the beach materials was tested by two dimensional model experiments with a movable bed. Finally, the three dimensional layout of detached breakwaters and submerged breakwaters were determined by two and three dimensional model experiments with movable beds.