We prepared main chain-type polyrotaxanes by urea bond-forming polyaddition of a diamine axle-containing alpha-cyclodextrin (alpha-CD)-based pseudo[3]rotaxane to a macromolecular diisocyanate derived from poly(propylene glycol). Bulky isocyanate or aniline used as a comonomer worked as an effective stopper during the key step of the polyrotaxane synthesis. In the polymer preparation, the chain extension method worked effectively to increase the polymerization degree. Polyrotaxane was modified by the main chain extension and the cross-linking of hydroxyl groups of the CD wheels. The morphology and the effect of the rotaxane structure on the thermal and physical properties were evaluated. Some polymers exhibited sufficient toughness for industrial use. Because diamine-type pseudo[3]rotaxane is easily obtained on a large scale (100 g in a 1 L flask) from a-CD and 1,12-diaminododecane, this study contributes to the synthesis of various polyrotaxanes for actual use.