  We investigate the gravitational collapse of a spherically symmetric,
inhomogeneous star, which is described by a perfect fluid with heat flow and
satisfies the equation of state $p=\rho/3$ at its center. In the process of the
gravitational collapsing, the energy of the whole star is emitted into space.
And the remaining spacetime is a Minkowski one without a remnant at the end of
the process. For a star with a solar mass and solar radius, the total energy
emitted is at the order of $10^{54}$ {\rm erg}, and the time-scale of the
process is about $8s$. These are in the typical values for a gamma-ray burst.
Thus, we suggest the gravitational collapse of a spherical star with heat flow
as a possible energy mechanism of gamma-ray bursts.
