In this paper, Sensitivity Method (SM) was used to the identification of boundary conditions. Particular attention in this paper was paid to the Levenberg‐Marquardt (L‐M) regularization method, because the inverse problems of the electromagnetic field are not well conditioned in typical cases. It was proved that using some information about the expected solution, the L‐M regularization method gives satisfactory results even in such cases where the singular value analysis (SVA) fails. The identified boundary conditions were compared with the results obtained by using the direct least squares (LS) method.