  We establish a conditional limit theorem for occupation times of infinite
ergodic transformations under a tied-down condition, that is, the condition
that the orbit returns to a reference set with finite measure at the final
observation time. The class of limit distributions is the generalization of the
uniform distribution which was discovered by M. Barlow, J. Pitman and M. Yor in
[S\'eminaire de Probabilit\'es XXIII. Lecture Notes in Mathematics, volume 1372
(1989), 294--314]. For the proof we utilize operator renewal theory. Our result
can be applied to intermittent maps with two or more indifferent fixed points.
