We have investigated nanosecond temporal responses of the cyclotron resonance signal of optically generated carriers in Cu2 O. The rise time is found to increase significantly as the excitation photon energy approaches to the phonon-assisted absorption edge of the 1s exciton. We model the generation of free carriers by two-body collisions of excitons, which leads to the reasonable estimation of the Auger coefficient. We also demonstrate the excitation spectroscopy of cyclotron resonance by using a two-photon transition to the even-parity excitonic states. Their dynamics is discussed based on the quantum-number dependence of the resonance linewidth.