  The tensor renormalization group attracts great attention as a new numerical
method that is free of the sign problem. In addition to this striking feature,
it also has an attractive aspect as a coarse-graining of space-time; the
computational cost scales logarithmically with the space-time volume. This fact
allows us to aggressively approach the thermodynamic limit. While taking this
advantage, we study the critical coupling of the two dimensional $\phi^{4}$
theory on large and fine lattices. We present the numerical results along with
the extrapolation procedure to the continuum limit and compare them with the
previous ones by Monte Carlo simulations.
