PURPOSE: To manufacture the Al alloy for a supporting substrate of a photo- conductive layer improving the dark decay of an electrophotographic sensitive body by incorporating specified ratio of Hf into Al.

CONSTITUTION: An Al alloy contg., by weight, 0.001 to 1.0%, preferably 0.1 to 0.8% Hf and the balance Al with inevitable impurities is prepd. Since the Al substrate manufactured by this Al alloy has about ≤4.1eV work function and there occurs a large difference between that and the work function of a photo-conductive layer, an electrophotographic sensitive body using this as the supporting substrate of a photo-conductive layer can obtain pictures of high quality.