Eleven Dimensional Superstring with New Supersymmetry and D=10 type 2A Green-Schwarz Superstring

A covariant action for closed D=11 superstring with local $\kappa$-symmetry and global supersymmetry transformations obeying the algebra $\{Q_\alpha,Q_\beta\}=C\Gamma^{\mu\nu}P_\mu n_\nu$ is suggested. Physical sector variables of the model and their dynamics exactly coincide with those of the D=10 type IIA Green-Schwarz superstring. It is shown that action of the D=10 type IIA Green-Schwarz superstring can be considered as a partially gauge fixed version of the D=11 superstring action.