A microfluidics chip is a miniature analytical system that injects a small amount of reagent into microchannels formed in the chip. It controls fluid flow to perform pretreatment, detection, reaction, mixing, separation, and analysis in parallel. In this study, polygonal microchannel structures were fabricated using a microstereolithography 3D printer based on an LCoS microdisplay projector. In the experiment, the width of the microchannel structure was changed from 50 ㎛ to 500 ㎛, and the output and width of the structure were measured. Inspection of the shape of the resulting microchannel structure showed that the tip of the structure was elliptical instead of the expected rectangular shape, and the fabrication width error increased as the channel width decreased to 200 ㎛ or less. Nevertheless, it was possible to fabricate microfluidics chip structures with widths less than 100 ㎛. The results of this study demonstrate the applicability of an LCoS microdisplay project-based 3D printer for the fabrication of microfluidic channel structures.