  We consider the simplest possibility for a model of particle dark matter in
which dark matter has only gravitational interaction with the standard model
sector. Even in such a case, it is known that the gravitational particle
production in an expanding universe may lead to a correct relic abundance
depending on the inflation scale and the mass of dark matter particle. We
provide a comprehensive and systematic analysis of the gravitational particle
production of fermionic and vectorial dark matter, and emphasize that particles
which are much heavier than the Hubble parameter but lighter than inflaton can
also be produced abundantly.
