  A pseudo-Nambu-Goldstone boson (pNGB) is an attractive candidate for dark
matter since the current severe limits of dark matter direct detection
experiments are naturally evaded by its nature. We construct a model with pNGB
dark matter based on a {\it gauged} $U(1)_{B-L}$ symmetry, where no ad-hoc
global symmetry is assumed. The model keeps natural suppression mechanism for
the dark matter direct detection cross section. On the other hand, the pNGB can
decay through the new high scale suppressed operators. We show that the pNGB
has long enough lifetime to be a dark matter in the wide range of the parameter
space of the model. The thermal relic abundance of pNGB dark matter can be fit
with the observed value against the constraints on the dark matter decays from
the cosmic-ray observations.
