A first sprocket is capable of engaging with a chain. The first sprocket has a first sprocket main body, a plurality of teeth disposed along a circumferential direction on the radially outer side of the first sprocket main body, and at least one shifting area. The teeth include at least one first tooth having a first maximum axial width and at least one second tooth having a second maximum axial width. The first maximum axial width is greater than the second maximum axial width. The first tooth is formed to be capable of engaging with an outer link plate of the chain. The second tooth is formed to be capable of engaging with an inner link plate of the chain.