It has been discussed that there is a structural change of polymer melt on a mesoscopic scale, such as the state of molecular entanglement, after applying melt processing. This may deteriorate the properties of the products from material-recycled polymers. On-line measurements of the high-speed melt spinning (HSMS) behavior of virgin and model-recycled polypropylene (PP) were performed to verify this concept; because the HSMS process is known to be sensitive to a slight difference in the state of molecular entanglement of molten polymers. Equipment for the simultaneous on-line measurements of the diameter and velocity of the spin-line with the capability of automatic tracking was applied for the precise and efficient measurement of spinning behavior. It was revealed that the crystallization behavior of recycled PP was slightly suppressed in comparison with the virgin PP in a low-speed region, while, that of the recycled PP was enhanced in the high-speed region, where so-called neck-like deformation occurred; suggesting that adopting the processing conditions with minimized influence on the mesoscopic structure is recommended in the preparation of original products.