  We derive the equation of motion for the relativistic compact binaries in the
post-Newtonian approximation taking explicitly their strong internal gravity
into account. For this purpose we adopt the method of the point particle limit
where the equation of motion is expressed in terms of the surface integrals. We
examine carefully the behavior of the surface integrals in the derivation. As a
result, we obtain the Einstein-Infeld-Hoffman equation of motion at the first
post-Newtonian (1PN) order, and a part of the 2PN order which depends on the
quadrupole moments and the spins of component stars. Hence, it is found that
the equation of motion in the post-Newtonian approximation is valid for the
compact binaries by a suitable definition of the mass, spin and quadrupole
moment.
