  The CP(N-1) \sigma\ model on finite interval of length R with Dirichlet
boundary conditions is analysed in the 1/N expansion. The theory has two
phases, separated by a phase transition at R ~ 1/\Lambda, \Lambda\ is dynamical
scale of the CP(N-1) model. The vacuum energy dependence of R, and especially
Casimir-type scaling 1/R, is discussed.
