Water-cluster molecules adsorbed on a Ru(0001) surface were studied by infrared reflection absorption spectroscopy (IRAS). Monomer and tetramer water clusters are stabilized on Ru(0001) at relatively wide coverage and temperature ranges. Annealing at higher temperatures than 170 K causes decomposition of the clusters into OH and H on the surface. Surface diffusion of those cluster molecules on Ru(0001) is deeply suppressed at low temperatures. Stretching frequencies observed at the bonded OD bands of root 3 x root 3 bilayer structures formed on Au(111), Pt(111) and Ru(0001) surfaces indicate that hydrogen-bonding interactions increase on those surfaces in this order due to the mismatch between metal and an ideal bilayer structure.