The velocity profile of dilute polymer solutions and a distilled water near the wall surface in a microchannel was clarified using evanescent wave illumination. Fluorescent particles with the diameter of 20 nm were used as tracer particles. The test polymers are polyethylene-oxide (SE-5, SE-15, SE-30 and SE-70) solution at 5 ppm. The results obtained for the velocity profile of a distilled water was found that the resolution of the velocity profile near the wall surface was drastically improved from the conventional results. On the other hand, the velocity profile of dilute polymer solutions increased significantly compared with that of distilled water, and the gradient of the velocity profile increased with the increase of the molecular weight of polymer.
