Technical Abstract: Recently, it has been found that some biopolymer solutions show aggregate formation or shear-induced mixing when they are exposed to shear field. An optical microscope was constructed for the study of these behaviors. A phase-contrast microscope is installed to obtain clear images from sample solutions where the refractive index difference of the domains is too small to be observed with common bright field microscopes. A modular type is adopted for the design of microscope for easy adjustment of optical components, alignment, and positioning it to the sample compartment. As a light source, a strobe type flash lamp is employed and its ignition is synchronized with CCD camera to avoid yielding smeared images. Shear fields are generated by a cone and plate geometry that is directly connected to a micro stepper motor with a controllable simple shear rate range of 0.025 to 2,500(1/s). In the case of oscillatory shear, accessible erange is 0 to 120 rad/s. A dual temperature controller allows temperature control of the sample compartment from ambient temperature to 200 degrees C with +/-0.1 degree C accuracy. Several starch solutions were used to demonstrate the performance and capability of the instrument.