Effect of Vector Meson Mass Decrease on Superfluidity in Nuclear Matter

$^1S_0$ pairing in nuclear matter is investigated by taking the hadron mass decrease into account via the ``In-Medium Bonn potential'' which was recently proposed by Rapp et al. The resulting gap is significantly reduced in comparison with the one obtained with the original Bonn-B potential and we ascertain that the meson mass decrease is mainly responsible for this reduction.