A polydimethylsiloxane microfluidic device enabling dual-view visualization is proposed and demonstrated. A prism with a 2mm square base was embedded beside a 300μm-wide microchannel. In addition to ordinary visualization from the top of the device, the microchannel could be viewed from the side, and its optical path was reflected to the top by the prism. The top and side dual visualization in a single field of view was then realized with a single objective lens. The shifts in the focal point in the top and side directions were modeled, and a compensation method utilizing a flat sheet was used. After simultaneous bright-field and dark-field visualization was attained, dual-view fluorescence imaging of the fluorescent solution and cells was realized.