On the Supersymmetry of Non-BPS D-brane

In this paper we extend the boundary string field theory action for a non-BPS D-brane to the one including the target space fermions and the nonlinear supersymmetry with 32 supercharges up to some order. This is based on the idea that the vacuum with a non-BPS D-brane belongs to the spontaneously broken phase of the supersymmetry. As a result, we find that the action is almost uniquely determined up to the field redefinition ambiguities.