High cycle fatigue properties of austenitic stainless steel SUS 304 were investigated for various conditions of cyclic stress amplitude σa-increasing tests under rotating bending and tension-compression loadings. Fatigue tests were also performed using specimens subjected to cyclic preloading. X-ray diffraction methods were utilized to measure the amount of martensitic transformation and residual stress. A marked effect of coaxing was observed under rotating bending tests and tension compression tests at 2 Hz. Stress-strain response revealed that the coaxing effect was caused by cyclic work hardening due to cyclic loading below the fatigue limit, but cyclic work softening due to temperature increase took place during stress cycling at the final step. Martensitic transformation was detected for some rotating bending specimens but not the tension compression specimens, which suggests that it is not the controlling behavior for the cyclic work hardening. Compressive residual stress was measured at the surface of the specimens exhibiting coaxing effect, which was considered to play an important role on the coaxing effect.