  We investigate possible precursory phenomena of color superconductivity in
quark matter at finite temperature T with use of a simple Nambu-Jona-Lasinio
model. It is found that the fluctuating pair field exists with a prominent
strength even well above the critical temperature T_c. We show that the
collective pair field has a complex energy located in the second Riemann sheet,
which approaches the origin as T is lowered to T_c. We discuss the possible
relevance of the precursor to the observables to be detected in heavy ion
collisions.
