Geomagnetic total force around Atotsugawa fault and Atera fault was observed by the proton magnetometer. Both faults are strike-slip faults of Quaternary age in central Japan and the average rates of displacement are more than 1m/10³ year. The characteristic magnetic total force associated with these faults were observed. Although large magnetic anomalies up to 300nT were observed along Atotsugawa fault, magnetic anomalies across Atera fault were about 10 to 80nT. The magnetic anomalies along Atotsugawa fault can be explained by the dyke model that the material with the magnetic susceptibility ranging from 10^-3 to 10^-2 (SI unit) intrudes along the fault plane. This material may be basic rock or rock contained iron minerals.