  We study the pairing correlations in a finite Fermi system from quantum
entanglement point of view. We investigate the relation between the order
parameter, which has been introduced recently to describe both finite and
infinite superconductors, and the concurrence. For a proper definition of the
concurrence, we argue that a possible generalization of spin flip
transformation is time reversal operation. While for a system with indefinite
number of particles concurrence is a good measure of entanglement, for a finite
system it does not distinguish between normal and superconducting states. We
propose that the expectation value of the radial operator for the total
pseudospin can be used to identify entanglement of pairing.
