  The Wess-Zumino model is analysed in the framework of the causal approach of
Epstein-Glaser. The condition of invariance with respect to supersymmetry
transformations is similar to the gauge invariance in the Z\"urich formulation.
We prove that this invariance condition can be implemented in all orders of
perturbation theory, i.e. the anomalies are absent in all orders. This result
is of purely algebraic nature. We work consistently in the quantum framework
based on Bogoliubov axioms of perturbation theory so no Grassmann variables are
necessary.
