We have investigated the spin-crossover behavior for [Fe(4-NH(2)trz)(3)] (p-CH3C6H4SO3)(2). nH(2)O. From the EXAFS measurement, it is confirmed that this complex has a linear chain polynuclear structure like the typical iron(II)-triazole complexes. In this complex, the number of crystal water, n, varies from 1.5 to 8 under the condition of water vapor pressure. The spin-crossover behavior in this complex strongly depends on the crystal water as well as the counter-anion. With increasing the number of crystal water from 1.5 to 8, the spin transition temperature decreases and the hysteresis width becomes narrower. In the case of n = 1.5. a stepped spin-crossover transition takes place and the intermediate spin state shows a unique thermal history.