A 3D seismic experiment was carried out in the Minaminoshiro area in Akita Prefecture, an area difficult of performing seismic exploration. This paper reports progresses during data processing and future problems. The data processing has executed static correction of 3D refraction, 3D DMO correction, and an F-X prediction filter processing on the data in time domain in the 3D seismic exploration as acquired in a spread of 4 km times 5 km in the subject area. The result of the data processing verified existence of a folding structure and the Noshiro thrust fault groups in the east to west direction, and locations of the Sakagawa fault associated therewith. Seen particularly noticeably was a structure having a slope falling north-ward at 15 to 35 degrees in shallow and deep portions on the east side of the Sakagawa fault in the south to north direction. In addition, the Dogiri fault was identified, which has been though to exist in a direction crossing perpendicularly the Noshiro thrust fault groups. It is scheduled that spatial velocity will be analyzed, and data processing will be conducted for deep regions. 7 figs.