Light Quark Masses to All Orders of Chiral Expansion

We study light (current) quark masses in framework of chiral constitutent quark model. In our calculation the current quark masses are defined uniquely, and all order effects of the light quark masses are considered. The results at energy scale $\mu=m_\rho$ are $m_s=(160\pm 15)$MeV, $m_s/m_d=20.2\pm 3.0$, $m_u/m_d=0.5\pm 0.09$.