  We show that it is possible to realize an inflationary scenario even without
conversion of the false vacuum energy to radiation. Such cosmological models
have a deflationary stage in which $Ha^2$ is decreasing and radiation produced
by particle creation in an expanding Universe becomes dominant. The preceding
inflationary stage ends since the inflaton potential becomes steep. False
vacuum energy is finally (partly) converted to the inflaton kinetic energy ,
the potential energy rapidly decreases and the Universe comes to the
deflationary stage with a scale factor $a(t) \propto t^{1/3}$. Basic features
and observational consequences of this scenario are indicated.
