  The gauge dependence of the renormalization group functions of the
Ginzburg-Landau model is investigated. The analysis is done by means of the
Ward-Takahashi identities. After defining the superconducting order parameter,
it is shown that its exponent $\beta$ is in fact gauge independent. This
happens because in d=3 the Landau gauge is the only gauge having a physical
meaning, a property not shared by the four-dimensional model where any gauge
choice is possible. The analysis is done in both the context of the
$\epsilon$-expansion and in the fixed dimension approach. It is pointed out the
differences that arise in both of these approaches concerning the gauge
dependence.
