  The initial data of gravity for a cylindrical matter distribution confined on
the brane is studied in the framework of the single brane Randall-Sundrum
scenario. In this scenario, 5-dimensional aspect of gravity appears in the
short range gravitational interaction. We found that the sufficiently thin
configuration of matter leads to the formation of the marginal surface even if
the configuration is infinitely long. This means that the hoop conjecture
proposed by Thorne does not hold in the Randall-Sundrum scenario; Even if a
mass $M$ does not get compacted into a region whose circumference in every
direction is ${\cal C}\le 4\pi GM$, black holes with horizons can form in the
Randall-Sundrum scenario.
