We have investigated introducing polyrotaxane (PR), a supramolecular material, into PMMA by polymer blending method. To the matrix resin 95 wt%, 5 wt% of PR was added. PLA, which is compatible with PMMA, was also added for the purpose of adjusting the yield behavior of the matrix resin. The blend material was prepared using a twin-screw melt-kneading extruder. The pelletized blend material was molded into dumbbell-shaped specimens by injection molding. Then, the internal structure observation and tensile test of the molded article and the Charpy impact test were carried out. Furthermore, the fracture surface of the test specimen after the physical property test was observed, and how the PR affected the physical properties was evaluated. As a result of TEM observation, PR was dispersed in the PMMA and PMMA / PLA matrices with a diameter of 200 nm or less. The transmittance of the specimen was 90%. As a result of the tensile test, PMMA, PLA and PMMA / PR hardly elongated and fractured. However, PMMA / PLA blend showed breaking elongation twe times that of neat PMMA. Furthermore, the PMMA / PLA / PR blend showed breaking elongation five times that of neat PMMA. By improving the breaking elongation of PMMA using PLA, the function of PR was developed and high breaking elongation was exhibited despite the addition of a small amount of 5%. SEM observation of the fracture surface revealed that in the PMMA / PLA / PR blend, a large amount of fine crazes was formed and the local stress concentration was alleviated. In the Charpy impact test, the effect of blending PR was hardly confirmed. As a result of observing the fracture surface of the test piece, almost no formation of craze was confirmed. In the case of high speed deformation, it is considered that the matrix resin was destroyed before PR effect was developed.