The vibrational spectra of the aniline-acetonitrile^+ and the aniline-acetonitrile-water^+ cluster cations have been measured by the infrared depletion spectroscopy in the frequency region of NH and OH stretching vibrations. One absorption band was observed at 3437cm^-^1 in the infrared spectrum of the aniline-acetonitrile^+ cluster cation, and was assigned to the NH stretching vibration of free NH of aniline. As for the aniline-water-acetonitrile^+ cluster cation, three absorptions were observed at 3722, 3634 and 3247cm^-^1, which were assigned to the anti-symmetric stretching and symmetric stretching vibrations of OH of water and the stretching vibrations of NH bond interacting with water, respectively. In the analysis of the vibrational spectrum, the structure of aniline-acetonitrile-water^+ cluster cation has been determined to be the hydrogen bonded structure between the hydrogen atoms of the NH2 group of aniline cation and the nitrogen atom in the CN group of acetonitrile and the oxygen atom of water. The predissociation of the aniline-acetonitrile-water^+ cluster cation have been found to give only one product channel dissociating into aniline-acetonitrile^+ and water.