  We present calculations of Casimir energy (CE) in a system of quantized
electromagnetic (EM) field interacting with an infinite circular cylindrical
shell (which we call `the defect'). Interaction is described in the only
QFT-consistent way by Chern-Simon action concentrated on the defect, with a
single coupling constant $a$.
  For regularization of UV divergencies of the theory we use % physically
motivated Pauli-Villars regularization of the free EM action. The divergencies
are extracted as a polynomial in regularization mass $M$, and they renormalize
classical part of the surface action.
  We reveal the dependence of CE on the coupling constant $a$. Corresponding
Casimir force is attractive for all values of $a$. For $a\to\infty$ we
reproduce the known results for CE for perfectly conducting cylindrical shell
first obtained by DeRaad and Milton.
