  We prove that the only finite factor-representations of the Higman-Thompson
groups $\{F_{n,r}\}$, $ \{G_{n,r}\}$ are the regular representations and scalar
representations arising from group abelianizations. As a corollary, we obtain
that any measure-preserving ergodic action of a simple Higman-Thompson group
must be essentially free. Finite factor representations of other classes of
groups are also discussed.
