  Reducing motion of particles to a two-dimensional potential problem, we show
that there are stable circular orbits around a squashed Kaluza-Klein black hole
with a spherical horizon and multi-Kaluza-Klein black holes with two spherical
horizons in five dimensions. For a single horizon, we show analytically that
the radius of an innermost stable circular orbit monotonically depends on the
size of an extra dimension. For two horizons, the radius of an innermost stable
circular orbit depends on the separation between two black holes besides the
size of an extra dimension. More precisely, the set of the stationary points of
the potential is composed of two branches. For a large separation, stable
circular orbits exist on the two branches regardless of the size of an extra
dimension, and in particular, on one branch, the set of stable circular orbits
is connected for the small extra dimension but has two disconnected parts for
the large extra dimension. For a small separation, only on one branch it
exists, and the radius of an innermost stable circular orbit monotonically
increases with an extra-dimension size.
