  In this paper, we prove the local converse theorem for split even special
orthogonal groups over a non-Archimedean local field of characteristic zero.
This is the only case left on local converse theorems of split classical groups
and the difficulty is the existence of the outer automorphism. We apply new
ideas of considering the summation of partial Bessel functions and overcome
this difficulty. As a direct application, we obtain a weak rigidity theorem for
irreducible generic cuspidal representations of split even special orthogonal
groups.
