  We examine the density-density correlation function in the Tomonaga-Luttinger
liquid state for the one-dimensional extended Hubbard model with the on-site
Coulomb repulsion $U$ and the intersite repulsion $V$ at quarter filling. By
taking into account the effect of the marginally irrelevant umklapp scattering
operator by utilizing the renormalization-group technique based on the
bosonization method, we obtain the generalized analytical form of the
correlation function. We show that, in the proximity to the gapped
charge-ordered phase, the correlation function exhibits anomalous crossover
between the pure power-law behavior and the power-law behavior with logarithmic
corrections, depending on the length scale. Such a crossover is also confirmed
by the highly-accurate numerical density-matrix renormalization group method.
