The accurate prediction of wave-induced currents is indispensible to analyze the beach deformation due to the sediment transport or dispersion in the surf zone, which often gives rises to serious environmental problems in the coastal region. Although many numerical models have been suggested up to now, it is not easy to properly simulate wave-induced currents, in particular, over a complex topography. In order to solve these problems, we have to understand the mechanism of wave transformation and wave-induced currents, to compare results numerical models with those of field measurements, and to find the validity and the applicability of them. And, also the validity of the model has been confirmed by the field investigation.