  We analyze the Kaluza-Klein type procedure in AdS$_3$ space called the
dimensional degression. The topological theory of the Fronsdal field in AdS$_3$
is reformulated in terms of the fields propagating in AdS$_2$. We find that the
Fronsdal field in AdS$_3$ leads to finitely many Kaluza-Klein modes. Namely,
the obtained spectrum is the massive Klein-Gordon and Proca fields in AdS$_2$.
The result is derived by using the specific mode expansion, the gauge fixing,
and 2-dimensional Schouten identities.
