  We formulate nonlinear perturbations of a scalar field dominated universe on
super-horizon scales. We consider the case of a single scalar field. We take
the gradient expansion approach. We adopt the uniform Hubble slicing and derive
the general solution valid to $O(\epsilon^2)$, where $\epsilon$ is the
expansion parameter associated with a spatial derivative, which includes both
the scalar and tensor modes. In particular, the $O(\epsilon^2)$ correction
terms to the nonlinear curvature perturbation, which become important in models
with a non-slowroll stage during inflation, are explicitly obtained.
