  Hawking effect of Dirac particles in a variable-mass Kerr space-time is
investigated by using a method called as the generalized tortoise coordinate
transformation. The location and the temperature of the event horizon of the
non-stationary Kerr black hole are derived. It is shown that the temperature
and the shape of the event horizon depend not only on the time but also on the
angle. However, the Fermi-Dirac spectrum displays a residual term which is
absent from that of Bose-Einstein distribution.
