A seismic survey with a high density network was performed by JARE-41 in the austral summer of 1999 to 2000. The seismic line is spread out over 190 km along the Mizuho traverse route. 160 seismic stations programmed on timer operation were installed. A clear reflection is obtained in some shot records. It was described as a PmP reflection in a previous study. This survey geometry enables us to apply reflection analysis. A single fold profile and corresponding velocity structures for the JARE-41 seismic line were obtained in this study. The dipping Moho reflector and dipping reflectivity layer are revealed beneath the full spread of the seismic line in the profile. The Moho reflector is located at approximately 42 km beneath the shot point S-6 and at approximately 29 km below sea level beneath the coastal end of the profile. There is a lateral change in reflection character in the reflective layer in the neighborhood of the shot point S-4, although the velocity of the upper crust from refraction analysis is constant in this region. The structure obtained might be one case of Seaward Dipping Reflector Sequences in the continental margin area of the past Gondwana super-continent.