We confirmed bulk-superconductivity of a ferromagnet UGe2 by the specific h
eat measurement, together with the measurements of the electrical resistivi
ty and ac susceptibility, in a pressure range from p = 1.0 to 1.5 GPa, wher
e the Curie temperature T-C(= 22-36 K) is still high, but another character
istic temperature T* is close to zero. In this pressure range, the heavy fe
rmion state is found to be formed at low temperatures.