Amorphous-alloy membranes of a series of Zr36-xHfxNi64 (0 less than or equal to x less than or equal to 36) were successfully prepared by the rapid-quenching method using a single roller; their amorphous structure and thermal behavior were characterized by XRD and DSC. All of the membranes, coated by palladium to provide activity to hydrogen dissociation and recombination, were sufficiently robust in a hydrogen atmosphere and showed stable permeability only to hydrogen at least in the range of 473-573 K. On the other hand, over 573 K, the permeation rate slowly decreased over time. Permeability was found to decrease with Hf substitute amount for Zr mainly due to increase in activation energy for permeation.