To provide a transmission with less noise and long service life.

The transmission 20 has an input shaft 21 and an output shaft 23. As a bearing for rotatably supporting a rotating part between the input shaft 21 and the output shaft 23, a sealed bearing having an outer ring 34, an inner ring 35, a rolling body 36 interposed between the outer ring 34 and the inner ring 35, and a seal mechanism 38 interposed between the outer ring 34 and the inner ring 35 and positioned in both sides of the rolling body 36 is used.