  We study spherically symmetric, asymptotically flat black hole solutions in
the low-energy effective heterotic string theory, which is the Einstein gravity
with Gauss-Bonnet term and the dilaton, in various dimensions. We derive the
field equations for suitable ansatz for general D dimensions and construct
black hole solutions of various masses numerically in D=4,5,6 and 10
dimensional spacetime with (D-2)-dimensional hypersurface with positive
constant curvature. A detailed comparison with the non-dilatonic solutions is
made. We also examine the thermodynamic properties of the solutions. It is
found that the dilaton has significant effects on the black hole solutions, and
we discuss physical consequences.
