With an objective to identify three-dimensionally resistivity in deep fault in the Mizunawa fault in Fukuoka Prefecture, a measurement was carried out by using the CSAMT method. The measurement was conducted by arranging seven traverse lines, each line having observation points installed at intervals of about 500 m. Among the 68 observation points in total, 33 points performed the vector measurement, and the remaining points the scaler measurement. For observation points having performed the vector measurement, polarized wave eclipses were depicted in the electric field to discuss which direction the current will prevail in. For analyses, a one-dimensional analysis was performed by using an inversion with smoothing restriction, and a two-dimensional analysis was conducted by using the finite element method based on the result of the former analysis. The vector measurement revealed that the structure in the vicinity of a fault was estimated to have become complex, and the two-dimensional analysis discovered that the Mizunawa fault is located on a relatively clear resistivity boundary. In addition, it was made clear that the high resistivity band may even be divided into two regions of about 200 ohm-m and about 1000 ohm-m. 2 refs., 7 figs.