  Let $f_1$ and $f_2$ be two semi-universal deformations of quasi homogeneous
polynomials in two variables respectively for the weight vectors $\rho_1$ and
$\rho_2$ such that they satisfy similar conditions to that of semi quasi
homogeneous singularities for one weight. By methods inspired by H.
Maynadier's, we give an explicit formula for a Bernstein-Sato polynomial
involving two affine forms $\rho_i(f_1) s_1 + \rho_i(f_2) s_2 +k$, $i=1,2$. In
the particular case $(f_1, f_2)=(x_1^a+x_2^b, x_1^c+x_2^d)$, we calculate the
space $\mathcal{H}_f$ recently studied by J. Brian\c{c}on, Ph. Maisonobe and M.
Merle and we show that it is equal to the zero set of $s_1 s_2 (ab s_1+ ad
s_2)(ad s_1+ cd s_2)$.
