The supramolecular network formation through inclusion complexation between a-cyclodextrin-based molecular tube (MT) and poly(ethylene oxide) monocetylether-graft-dextran (5C(16)PEO-g-Dex40) was demonstrated. From isothermal titration calorimetric (ITC) measurement, it was confirmed that MT formed an inclusion complex with two C16PEO side chains in 5C(16)PEO-g-Dex40. From viscosity measurements, the specific viscosity of the solution containing MT and 5C(16)PEO-g-Dex40 was much larger than that containing 5C(16)PEO-g-Dex40. It is considered that MT participates in the supramolecular network formation of 5C(16)PEO-g-Dex40 through inclusion complexation with two C16PEOs grafted to independent Dex40s.