  We analyse the recent claim that a violation of a Bell's inequality has been
observed in the $B$--meson system [A. Go, {\em Journal of Modern Optics} {\bf
51} (2004) 991]. The results of this experiment are a convincing proof of
quantum entanglement in $B$--meson pairs similar to that shown by polarization
entangled photon pairs. However, we conclude that the tested inequality is not
a genuine Bell's inequality and thus cannot discriminate between quantum
mechanics and local realistic approaches.
