A transmission 7 includes three ball bearings 81A, 81B, 81C, an input shaft 74, an output holding member 83, and an output shaft 72. Each of the ball bearings 81A, 81B, 81C has an inner race, an outer race, and a plurality of rolling elements. The input shaft 74 has an insertion portion inserted into the inner race, and is rotated about the rotation axis of the ball bearing 81A, thereby rotating the inner race. When the inner race is rotated, the rolling elements roll in accordance with the rotation of the inner race. The output holding member 83 includes a holding portion 831 which is held by the rolling elements, and is rotated about the rotation axis of the ball bearing 81C in accordance with rolling of the rolling elements, whereby the output shaft 72 is rotated about the rotation axis of the ball bearing 81C.