Unstained histological sections were used for histological image analysis. Color differences among sections and discoloration which sometimes degrade the accuracy for image analysis don’t occur in unstained sections. Staining process can also be omitted. A multimodal method is proposed to analyze unstained histological sections. The feature of our multimodal method is to use the imaging methods available in an optical microscope used in dairy diagnosis. Three kinds of images, bright-field, dark-field, and phase-contrast images were used. These images could be easily captured using a commonly available optical microscope with little additional time and cost. The method was applied for cell membrane extraction of unstained hepatic histological sections. The best result was obtained when all three kinds of images were combined, showing the effectiveness of multimodal method for analyzing unstained sections. Average correct rate was almost the same as the case which has ever been obtained for HE-stained sections. These results show promising possibility of using unstained sections for histological image analysis.