  We discuss shear viscosity of the quark matter by using Kubo formula. The
shear viscosity is calculated in the framework of the quasi-particle RPA for
the Nambu-Jona-Lasinio model. We obtain a formula that the shear viscosity is
expressed by the quadratic form of the quark spectral function in the chiral
symmetric phase. The magnitude of the shear viscosity is discussed assuming the
Breit-Wigner type for the spectral function.
