This report deals with the storm tide in Suruga Bay, which is facing the Pacific Ocean and is often attacked by typhoon.
　The main part of the study is numerical calculation of storm tide with an electronic computer. The principle is to obtain the water level and velocity variation under the dynamic action of wind stress and atmospheric pressure due to typhoon, solving the difference equations of motion and of continuity for sea water. The distribution of wind speed, wind direction and atmospheric pressure as external forces in typhoon area is given as a function of time using semi-empirical formulas established by Japan Meteorological Agency.
　Two typical typhoons were selected for the calculation, namely typhoon 5915 and typhoon 6626. The former attacked Nagoya district in September 1959 and is regarded the biggest typhoon ever observed in Japan. Although the magnitude of this Ise-bay typhoon was the severest, the actural route was not the worst one for Suruga Bay. In calculation, however, this typhoon was assumed to pass along an imaginary route wastward to the bay so as to get the worst condition for the bay. The latter is as typhoon which actually brought various damages to the bay in September 1966.
　The mesh interval for numerical calculation is 4 km inside the bay and 12 km in the outer sea. The time interval is 20 seconds. The calculation was started from the initial condition, where the centre of the typhoon is located far from the computed area and the water level elevation is given by the atmospheric pressure depression.
　The computed results show that the strom tide is mostly caused by atmospheric pressure depression and the effect of wind setup is negligible owing to the extremely big water depth in the bay. This conclusion is certified by actual tidal records in the past, which have been collected from tide observatories and are presented in this report together with meteorological data. In some ports, however, water level elevation due to wave breaking along the neighbouring coast is added to the meteorological tide. The secondary undulation also affects the instantaneous water level in a basin.
　The final value of storm tide, if attacked by Ise-bay typhoon, is estimated to be 0.7 m in general, 1.5～2.0 m with the effect of breaking wave in the surf zone, and about 0.5 m more when the secondary undulation is taken into account.