CP Violation in Neutrinoless Double Beta Decay and Neutrino Oscillation

Taking account of possible CP violation, we discuss about the constraints on the lepton mixing angles from the neutrinoless double beta decay and from the neutrino oscillation for the three flavour Majorana neutrinos. From the CHORUS oscillation experiment, combined with the data of neutrinoless double beta decay, we show that the large angle solution of (\theta_{23}) is improbable if the neutrino mass (m_3) of the third generation is a candidate of hot dark matters.