  We consider graphene bilayer in a constant magnetic field of arbitrary
orientation (i.e. tilted with respect to the graphene plane). In the low energy
approximation to tight binding model with Peierls substitution, we find the
exact spectrum of Landau levels. This spectrum is two-fold degenerate in the
limit of large in-plane field, which gives rise to a new SU(2) symmetry in this
limit.
