  We present a novel mechanism to generate the cosmic perturbation from
evaporation of primordial black holes. A mass of a field is fluctuated if it is
given by a vacuum expectation value of a light scalar field because of the
quantum fluctuation during inflation. The fluctuated mass causes variations of
the evaporation time of the primordial black holes. Therefore provided the
primordial black holes dominate the universe when they evaporate, primordial
cosmic perturbations are generated. We find that the amplitude of the large
scale curvature perturbation generated in this scenario can be consistent with
the observed value. Interestingly, our mechanism works even if all fields which
are responsible for inflation and the generation of the cosmic perturbation are
decoupled from the visible sector except for the gravitational interaction. An
implication to the running spectral index is also discussed.
