A gear is provided that is capable of suppressing a decrease in strength at a weld line. The gear (40) is provided with a cylindrical boss (41) that is formed at a center portion, a rim (42) that is formed on an outer side in a radial direction of the boss concentrically with the boss and has a tooth portion (42a) at an outer circumferential portion thereof, and a web (43) that links the boss and the rim. In the web, a plurality of gate marks (43a) are formed. Furthermore, in the web, there are provided a plurality of first radial direction ribs (43b) that extend from the boss to the outer side in the radial direction along a weld line (40a) that appears between adjacent ones of the gate marks.