The flap type gate has been developing as storm surge and tsunami countermeasure. Because the flap type gate closes a harbor quickly, it is thought to be effective as a tsunami countermeasure. However, there are some uncertainties in the hydraulic and hydrodynamic characteristics against tsunami. In this paper, two-dimensional hydraulic tests were carried out on the model of scale 1/60 in the water channel with wave maker, and wave pressure and gate behavior of the flap type gate were investigated. As a result, it confirmed that a modified flap type gate was effective as a tsunami countermeasure.
