  We present ALMA observations of a diffuse gas tracer, CO(J = 1-0), and a
warmer and denser gas tracer, CO(J = 3-2), in the overlapping region of
interacting galaxies NGC 4567/4568, which are in the early stage of
interaction. To comprehend the impact of galaxy interactions on molecular gas
properties, we focus on interacting galaxies during the early stage and study
their molecular gas properties. In this study, we investigate the physical
states of a filamentary molecular structure at the overlapping region, which
was previously reported. Utilising new higher-resolution CO(J = 1-0) data, we
identify molecular clouds within overlapping and disc regions. Although the
molecular clouds in the filament have a factor of two higher an average virial
parameter (0.56+-0.14) than that in the overlapping region (0.28+-0.12) and in
the disc region (0.26+-0.16), all identified molecular clouds are
gravitationally bound. These clouds in the filament also have a larger velocity
dispersion than that in the overlapping region, suggesting that molecular gas
and/or atomic gas with different velocities collide there. We calculate the
ratio of the integrated intensity of CO(J = 3-2) and CO(J = 1-0) (= R3-2/1-0)
on the molecular cloud scale. The maximum R3-2/1-0 is 0.17+-0.04 for all
identified clouds. The R3-2/1-0 of the molecular clouds in the filament is
lower than that of the surrounding area. This result contradicts the
predictions of previous numerical simulations, which suggested that the
molecular gas on the collision front of galaxies is compressed and becomes
denser. Our results imply that NGC 4567/4568 is in a very early stage of
interaction; otherwise, the molecular clouds in the filament would not yet
fulfil the conditions necessary to trigger star formation.
