The infrared spectrum of aniline-water-pyrrole cluster cation has been measured in the 3 mum region. Four strong vibrational bands were observed at 3313, 3515, 3637, and 3721 cm(-1), and the cluster dissociated into fragments in two reaction paths, AWP(+) --> AW(+) + P and AWP(+) --> AP(+) + W (A: aniline, W: water, P: pyrrole) when it absorbed an infrared photon. The branching ratio (AW(+)/AP(+)) has been determined to be 0.20 +/- 0.02 for the NH stretching vibration of aniline (3313 cm(-1), hydrogen-bonded to pyrrole) and 0.14 +/- 0.03 for the other three bands. This vibrational mode dependence should be due to the fast energy transfer from the NH to the intermolecular vibration through the hydrogen bond.