  We investigate the metal-insulator transition of the (1+1)-dimensional
Hubbard model in the path-integral formalism with the tensor renormalization
group method. The critical chemical potential $\mu_{\rm c}$ and the critical
exponent $\nu$ are determined from the $\mu$ dependence of the electron density
in the thermodynamic limit. Our results for $\mu_{\rm c}$ and $\nu$ show
consistency with an exact solution based on the Bethe ansatz. Our encouraging
results indicate the applicability of the tensor renormalization group method
to the analysis of higher-dimensional Hubbard models.
