  With simple but exactly solvable model, we investigate the supercurrent
transferring through the c-axis cuprate superconductor-normal
metal-superconductor junctions with the clean normal metal much thicker than
its coherence length. It is shown that the supercurrent as a function of
thickness of the normal metal decreases much slower than the exponential
decaying expected by the proximity effect. The present result may account for
the giant proximity effect observed in the c-axis cuprate SNS junctions.
