  We perform the complete canonical analysis of the tetrad formulation of
bimetric gravity and confirm that it is ghost-free describing the seven degrees
of freedom of a massless and a massive gravitons. In particular, we find
explicit expressions for secondary constraints, one of which is responsible for
removing the ghost, whereas the other ensures the equivalence with the metric
formulation. Both of them have a remarkably simple form and, being combined
with conditions on Lagrange multipliers, can be written in a covariant way.
