  The Hamiltonian approach is developed for QCD_2 in the limit of infinite
number of colours N_C ('t Hooft model). Bosonization of the theory is performed
explicitly and the generalized Bogoliubov transformation for the composite
boson operators is introduced and used to bring the Hamiltonian into diagonal
form in the two-body sector. The resulting theory is re-formulated in terms of
effective degrees of freedom and describes the free mesons with creation and
annihilation operators commuting in the canonical way. Corrections in N_C to
the leading term in the Hamiltonian describe the interaction between mesons and
can be used to consider their decays. Chiral properties of the theory are
discussed and it is shown that the backward motion of the chiral pion
(Goldstone mode) is not suppressed and should contribute to the decays
amplitudes.
