To investigate the corrosion behavior of the stainless steel joints brazed with nickel-based brazing filler metals in the heat exchanger, electrochemical measurement of SUS316L and filler metals were carried out. BNi-5 (Ni-Cr-Si alloy) and FP-613 (Ni-Cr- P-Si alloy) filler metals were prepared as nickel-based brazing filler metals. Corrosion potential, galvanic current and polarization curves of SUS316L, BNi-5 and FP-613 were measured in a 0.06 mol/L NaCl solution at 25℃ and 80℃. After the measurement, the microstructures of specimens were observed with an electron probe X-ray micro analyzer (EPMA). As a result, it was found that BNi-5 preferentially dissolves in the SUS316L joint with BNi-5 filler, and SUS316L preferentially dissolves in the joint with FP-613 filler in the NaCl solution. The EPMA analysis clarified that Si-rich Ni-Si-Cr-Fe phases and the Cr and P-rich phases preferentially dissolve in BNi-5 and FP-613, respectively.