In this paper, we first investigate the shape operators of certain kind of orbits of the
isotropy action of a semi-simple pseudo-Riemannian symmetric space. The investigation is
performed by investigating the complexified action. Next, by using the fact obtained by
the investigation, we show that certain kind of principal orbits of a Hermann type action
on a semi-simple pseudo-Riemannian symmetric space are curvature-adapted proper complex
equifocal submanifolds and that their shape operators are semisimple. It follows from this
fact that the principal orbits are isoparametric submanifolds with flat section. Also, we
derive an interesting structure of a semi-simple pesudo-Riemannian symmetric space (in
particular, the complexification of a Riemannian symmetric space) from two special Hermann
type actions on the space.