We bridge between submanifold theory and contact geometry.  
We give a geometric meaning of some fundamental notions such as Sasakian, nearly 
Sasakian, $K$-contact from the viewpoint of the result in \cite{MO} (Theorem 1).
Moreover, motivated by the notion of totally $\eta$-umbilic hypersurfaces 
in a nonflat complex space form, we give a new notion in contact geometry (Theorem 2).