PURPOSE: To provide a technology for obtaining a resin having a 'long fiber reinforced thermoplasticity' in which the interfacial adhesiveness of a fiber-like substance with thermoplastic resin is good by adding a small amount of a third component.

CONSTITUTION: The manufacturing method of thermoplastic resin reinforced by a continuous fiber-like substance existing in parallel with the major axial direction of pellets comprises two steps consisting of a step bringing a substance, which can form a covalent bonding with a chemical functional group existing on the surface of the continuous fiber-like substance, into contact with the continuous fiber-like substance and a step bringing the continuous fiber-like substance thus prepared into contact with a thermoplastic resin.