PROBLEM TO BE SOLVED: To provide a fiber-reinforced resin gear which does not increase processing costs of a mold for injection molding and allows improvement of the circularity without reduction of the degree of freedom of design and its injection molding method.SOLUTION: A plurality of ejector pins 14 are protruded before injection of a molten resin containing a reinforcing fiber from a pin-point gate 13, in a web formation part 3A within a cavity 10 and at a position on the outer side in the radial direction relative to the pin-point gate 13. After the flow of the molten resin containing the reinforcing fiber injected into the cavity 10 from the pin-point gate 13 impinges on the ejector pins 14 is branched and before a gear formation part 4A within the cavity 10 is filled with the molten resin containing the reinforcing fiber, the ejectors 14 are made to retreat from the inside of the cavity 10. A weld-line 16 extending in the radial direction is formed at a position on the outer side in the radial direction relative to the ejector pins 14, and retreat parts of the ejector pins 14 are filled with the molten resin.
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