  We construct the world-volume action for non-BPS D-branes in type II string
theories. This action is invariant under all the unbroken supersymmetries in
the bulk, but these symmetries are realised as spontaneously broken symmetries
in the world-volume theory. Coupling of this action to background supergravity
fields is straightforward. We also discuss the fate of the U(1) gauge field on
the D-brane world-volume after tachyon condensation.
