Infrared photodissociation spectra of (benzene-water-Ar)(+) in the 3 mum region were observed by monitoring benzene(+) and (benzene-water)(+) fragments. The spectral features showed that the Ar atom locates on the benzene ring, preserving the same structure as that of (benzene-water)(+), in which the water moiety is bound to the side of benzene(+) by the charge-dipole interaction and C-(HO)-O-... hydrogen bonds. We evaluated the binding energy of (benzene-water)(+) to be D-0 = 3290 +/- 120 cm(-1) by analyzing the appearance energy dependence of the fragments. The binding energy of the cluster cation gave us the adiabatic ionization potential of the neutral (benzene-water) cluster, IP0 = 72160 +/- 150 cm(-1).