The relationship between the dynamic and static flexural rigidities of fabrics was discussed. The dynamic rigidity was measured by a vibrating-reed method, and the static one by a KES pure bending test. The static flexural rigidity was found to be several times as large as the dynamic one. The maximum curvature of the vibration strip of a fabric was calculated from the measured displacement and the value at a fixed point was used for the comparison of the flexural rigidity. The maximun curvature was very small and corresponded to the initial curve region in the KES test. The mean rigidity of a fabric in the cyclic bending process within a small curvature range was estimated with the aid of a model hysteresis curve. The estimated rigidity decreased with increase in the maximum curvature, and was well in qualitative correlation but not in quantitative agreement with the measured dynamic rigidity. The actual mean curvature was smaller than the estimated value, the reason of which was attributed to the fact that the maximun curvature was distributed along the longitudinal direction on the vibrating strip.