In this paper, the multiplicativity of the partially polarized image-plane speckle noise is considered. After deriving the n-th order moment of the intensity of the speckled image, the multiplicative model of speckle noise is justified. The mean squared error of the model for partially polarized case is discussed. Finally, the validity of the multiplicative model for the incoherent superposition of n independent linearly polarized speckled images formed with identical illumination is treated.