An equilibrium structure of the charge-transfer (CT) state of (p-cyanophenyl)pentamethyldisilane was determined by transient infrared absorption spectroscopy of its CH stretching vibration region, and by the spectral simulation with quantum chemical calculations. It was found that a pattern of the CH stretching vibration bands of the CT state is substantially different from that of the So state. This band feature of the CT state was well reproduced assuming the planar sigma(si)_(si)pi* state, where the disilanyl group and the phenyl ring lie in the same plane. Considering that the disilanyl group in the So and the locally excited pi pi* states lie in the plane perpendicular to the phenyl ring, an occurrence of a twisting-type structural change during the ICT process was experimentally identified in the present study.