We observed that AC susceptibility of a weak random anisotropy magnet (weak RAM), amorphous NdGdFe, strongly depends on the excitation field, h 0 ; with increasing h 0 from 0.1 to 1Oe, both Reχ 0 and Imχ 0 become several times larger, and the ratio of Imχ 0 to Reχ 0 increases from about 0.1 to 1.0, suggesting that the average relaxation time becomes much longer by h 0 . In addition, peak temperature width of Reχ 0 broadens extremely and the peak temperature of Imχ 0 shifts to lower temperature side. A characteristic relaxation time τ c , obtained for different h 0 by using the Cole–Cole analysis, has two anomalies at T c1 and T c2 with keeping a fairly long relaxation time between T c1 and T c2 . These phenomena in a weak RAM were discussed in terms of the free energy structure with small height of barriers comparable with h 0 .