  The magnetic field created in high energy nuclear collisions will affect the
dynamical processes in the QCD medium, especially the heavy quark production
that happens in the initial stage of the collisions. We calculate in a strong
magnetic field the heavy quark production cross section for the elementary
process gg {\rightarrow} Q{\bar Q} at leading order and the corresponding
transverse momentum distribution in nucleus-nucleus collisions. In comparison
to the QED process, the heavy quark production is dominated by the unique QCD
channel with gluon self-interaction. Due to the dimension reduction of quark
phase space in a strong magnetic field, the production is concentrated in a
very narrow energy region above the threshold. Since the translation invariance
is broken, the production becomes anisotropic in magnetic field.
