  The Hawking temperature for the Schwarzschild black hole is divergent when
the mass of the black hole vanishes; however the corresponding geometry becomes
the Minkowski spacetime whose intrinsic temperature is zero. In connection with
this issue, we construct a non-singular temperature which follows the Hawking
temperature for the large black hole while it vanishes when the black hole
completely evaporated. In order for thermodynamic significances of this
modified temperature, we calculate thermodynamic quantities and study phase
transitions. It turns out that even the small black hole can be stable below a
certain temperature, and the hot flat space is always metastable so that it
decays into the stable small black hole or the stable large black hole.
