Nanofiber aggregation were observed under simple shear, which was generated by rheometer. The rheometer used has parallel plates and cone-and-plates geometries. The Nanofiber (bacteria cellulose fiber) having 50 nm in diameter was extracted from nata de coco and suspended uniformly at 0.5 wt% concentration to glycerin. The torque, which was measured by rheometer, continued to increase with time and did not stay at constant value during 10 minutes of measurement. This is because the nanofibers were formed into wormlike aggregation and it enlarged with time. The diameter of the wormlike aggregation became 1.4 times greater than the length between parallel plates at the end of measurement.