  The stability of a Nambu-Goto membrane at the equatorial plane of the
Reissner-Nordstr{\o}m-de Sitter spacetime is studied. The covariant
perturbation formalism is applied to study the behavior of the perturbation of
the membrane. The perturbation equation is solved numerically. It is shown that
a membrane intersecting a charged black hole, including extremely charged one,
is unstable and that the positive cosmological constant strengthens the
instability.
