Rotary bending fatigue tests of Type 304 steel in 1 N H₂SO₄ containing 0.5 M NaCl at 25°C were conducted in order to study the corrosion crack initiation at the site of a growing pit, in comparison with that in the active potential range. Cracks are found to initiate even at a potential of 0.42 V which is more noble than the critical pitting potential, V_c=0.41 V (SCE). In the study of the crack initiation at the pits growing at the potentials less noble than V_c, the following procedures were adopted. The precracks with appropriate depths, which had been introduced into the specimen at −0.45 V, developed into hemispherical pits and continued to grow at the passive potentials. Such growing pits are considered to be equivalent to the natural pits growing in the same potential range. The occurrence of crack initiation at the bottom of the growing pits increased markedly in the potential range between 0.1 and 0.3 V under the condition of potential descent at the sweep rate of 240 min/V. The fact that the less noble the potential the less deep pits issue cracks could be explained from the requirement that initiating crack must have a growth rate higher than the dissolution rate at the pit bottom. The initiation sites of cracks were observed to be small crystallographic pits with mixed facets of {111} and {100} formed at the bottom of growing pits during the potential descent. The (100) faceting dissolution at the wall of crystallographic pits would play an important role in crack initiation, as it does in crack initiation in the active potential range.