With an idler, a first member includes a first boss portion, a first rim portion, and a side plate. A second member includes a second boss portion, a second rim portion, and a side plate. A third member includes a third boss portion having a third axle hole portion configured to allow insertion of an axle. The third boss portion is disposed between the first boss portion and the second boss portion. A first welded portion is formed between the second boss portion and the third boss portion and connects the second and third boss portions. A second welded portion is formed between the first boss portion and the third boss portion and connects the first and third boss portions. A third welded portion is formed between the first rim portion and the second rim portion and connects the first and second rim portions.