  We investigate the possibility of identifying massive objects (lenses) in the
Galactic Center region (GC) by means of pulsar timing. The well known intensity
change due to microlensing is found to be less important. For typical stellar
masses, the flux magnification can be significant only if the lens passes very
close to the pulsar--Earth axis. We show that in the case of a pulsar the time
varying travel-time delay, which is observable because of the pulsating nature
of pulsar radiation, is a much more powerful tool to investigate mass
distributions in the GC. We find that a travel-time delay is measurable even
for rather large distances between the lens and the pulsar--Earth axis.
  The time varying travel-time delay can be used to determine the mass of the
lens and the ratio of the transverse velocity to the minimum impact parameter.
Based on Monte Carlo simulations of synthetic data sets we give the expected
accuracies in the parameter determination for various masses.
  We argue that pulsars found behind the very center of our Galaxy would
provide an excellent opportunity to test the mass distribution in the Galactic
nucleus, and therefore to distinguish between a super massive black hole (SMBH)
and a super-dense star cluster (SDSC) within the central 0.1 pc.
