  Effects caused by the event-by-event fluctuation of the initial conditions in
hydrodynamical description of high-energy heavy-ion collisions are
investigated. Non-negligible effects appear for several observable quantities,
even for a fixed impact parameter $\vec b $. They are sensitive to the equation
of state, being the dispersions of the observable quantities in general smaller
when the QGP phase appears at the beginning of hydrodynamic evolution than when
the fluid remains hadron gas during whole the evolution.
