  We present a new supersymmetric integrable model: the $N=2$ superconformal
affine Liouville theory. It interpolates between the $N=2$ super Liouville and
$N=2$ super sine-Gordon theories and possesses a Lax representation on the
complex affine Kac-Moody superalgebra ${\hat {sl(2| 2)^{(1)}}}$. We show that
the higher spin $W_{1+\infty}$-type symmetry algebra of ordinary conformal
affine Liouville theory extends to a $N=2\; W_{1/2 + \infty}$-type
superalgebra.
