A multiple exposure immersion method for contour mapping is proposed that improves the accuracy of the measurement by means of interference fringes sharpening. The method is based on recording of the multiple exposure holograms of the object which was put into the immersion chamber with equal changes of a refractive index between the exposures. For the purpose of the full or partial suppression of the side maxima of the interference pattern the change of the object wave amplitude from one exposure to another is proposed. It is shown that this is equal to the change of the exposure time of the object and reference waves. This method is confirmed by experimental data.