A novel method for analyzing optical characteristics of an optical medium including illuminating an optical medium, having an input surface and an output surface of light, with at least three input light beams differed from each other in a polarization state, respectively from a direction inclined by a polar angle .theta. (0.degree.<.theta.<90.degree.) with regard to the input surface; obtaining polarization states of output light beams coming out from the output surface, corresponded to the input light beams; and determining the Jones matrix M which can satisfy the equation (1) below with polarization vectors of the input light beams and polarization vectors of the output light beams:'''.times..times..times. ##EQU00001##