  We show renormalization group invariants in neutrino sector. These are found
from a simple analytical discussion of Majorana mass matrix for light
neutrinos. It is shown that the invariants are obtained by taking ratios among
elements of the Majorana neutrino mass matrix. The invariance is independent of
neutrino mass ordering and a parameterization of mixing matrix for the lepton
sector. Parameters in the runnings under renormalization group equations in the
neutrino sector are also analyzed.
