  We investigate properties of the conserved charge in general relativity,
recently proposed by one of the present authors with his collaborators, in the
inflation era, the matter dominated era and the radiation dominated era of the
expanding Universe. We show that the conserved charge in the inflation era
becomes the Bekenstein-Hawking entropy for de Sitter space, and it becomes the
matter entropy and the radiation entropy in the matter and radiation dominated
eras, respectively, while the charge itself is always conserved. These
properties are qualitatively confirmed by a numerical analysis of a model with
a scalar field and radiations. Results in this paper provide more evidences on
the interpretation that the conserved charge in general relativity corresponds
to entropy.
