  We apply the higher-order tensor renormalization group to the lattice
CP($N-1$) model in two dimensions. A tensor network representation of the
CP($N-1$) model in the presence of the $\theta$ term is derived. We confirm
that the numerical results of the CP(1) model without the $\theta$ term using
this method are consistent with that of the O(3) model which is analyzed by the
same method in the region $\beta \gg 1$ and that obtained by the Monte Carlo
simulation in a wider range of $\beta$. The numerical computation including the
$\theta$ term is left for future challenges.
