  The amplitude for scalar Higgs boson production in a fusion of two off-shell
gluons is calculated including finite (not infinite) masses of quarks in the
triangle loop. In comparison to the effective Lagrangian approach, we have
found a new term in the amplitude. The matrix element found can be used in the
kt-factorization approach to the Higgs boson production. The results are
compared with the calculations for on-shell gluons. Small deviations from the
cos(phi)^2-dependence are predicted. The off-shell effects found are
practically negligible.
