Masaki Izumi - Kyoto University Connes-Takesaki introduced the notion of the flow of weights for a factor, which is an ergodic flow, and It is known to be a complete isomorphism invariant for injective type III factors. On the other hand, it is not so easy to compute the flows for concrete examples except for a few cases. In this talk, we describe the flows of weights for von Neumann algebras arising from KMS states for the gauge actions of the Cuntz-Pimsner algebras in terms of Poisson (tail) boundaries.