  The cosmological scenario of the dark matter generated in the hidden gauge
theory based on the grand unification is discussed. It is found that the
stability of the dark matter halo of our Galaxy and the cosmic ray observation
constrain, respectively, the dark matter mass and the unification scale between
the standard model and the hidden gauge theory sectors. To obtain a
phenomenologically consistent thermal evolution, the entropy of the standard
model sector needs to be increased. We therefore propose a scenario where the
mini-inflation is induced from the potential coupled to the Standard model
sector, in particular the Higgs sector. This scenario makes consistent the
current dark matter density as well as the baryon-to-photon ratio for the case
of pion dark matter. For the glueball or heavy pion of hidden gauge theory, an
additional mini-inflation in the standard model sector before the leptogenesis
is required. We also propose the possibility to confirm this scenario by known
prospective experimental approaches.
