  A pattern of deviations in coupling constants of Standard Model (SM)-like
Higgs boson from their SM predictions indicates characteristics of an extended
Higgs sector. In particular, Yukawa coupling constants can deviate in different
patterns in four types of Two Higgs Doublet Models (THDMs) with a softly-broken
Z_2 symmetry. We can discriminate types of THDMs by measuring the pattern of
these deviations. We calculate Yukawa coupling constants of the SM-like Higgs
boson with radiative corrections in all types of Yukawa interactions in order
to compare to future precision data at the International Linear Collider (ILC).
We perform numerical computations of scale factors, and evaluate differences
between the Yukawa couplings in THDMs and those of the SM at the one-loop
level. We find that scale factors in different types of THDMs do not overlap
each other even in the case with maximum radiative corrections if gauge
couplings are different from the SM predictions large enough to be measured at
the ILC. Therefore, in such a case, we can indirectly determine the type of the
THDM at the ILC even without finding additional Higgs bosons directly.
