It is an object to establish a test method that enables a high-concentration ammonium bisulfide environment to be reproduced at a laboratory level, and enables the corrosivity of a material to be evaluated easily and highly accurately. According to the test method, when evaluating the corrosion resistance of a material under an ammonium bisulfide environment, the corrosion resistance of the material is evaluated by simulating the relationship between the ammonium bisulfide concentration of a test solution and the pressure in advance, and then determining the ammonium bisulfide concentration from the pressure.