  Phase diagram of a chiral random matrix model with the degenerate ud quarks
and the s quark at finite temperature and density is presented. The model
exhibits a first-order transition at finite temperature for three massless
flavors, owing to the U_A(1) breaking determinant term. We study the order of
the transition with changing the quark masses and the quark chemical potential,
and show that the first-order transition region expands as the chemical
potential increases. We also discuss the behavior of the meson masses and the
susceptibilities near the critical point.
