  Low energy spectrum of the S=1 kagom\'e Heisenberg antiferromagnet (KHAF) is
studied by means of exact diagonalization and the cluster expansion. The
magnitude of the energy gap of the magnetic excitation is consistent with the
recent experimental observation for \mpynn. In contrast to the $S=1/2$ KHAF,
the non-magnetic excitations have finite energy gap comparable to the magnetic
excitation. As a physical picture of the ground state, the hexagon singlet
solid state is proposed and verified by variational analysis.
