The Xi_Q - Xi_Q' Mixing and Heavy Baryon Masses

We examine the $\Xi_Q - \Xi'_Q$ mixing and heavy baryon masses in the heavy quark effective theory with the $\mq$ corrections. In the conventional baryon assignment, we obtain the mixing angle $\cos^2 \theta = 0.87\pm 0.03$ in virtue of the Gell-Mann-Okubo mass relation. On the other hand, if we adopt the new baryon assignment given by Falk, the allowed region of the $\Sigma_c$ mass is upper from 2372 MeV.