A gear mechanism according to the invention includes a first shaft, a second shaft disposed at an angle with the first shaft, a first gear group including a plurality of first gears that transmit rotation of the first shaft to the second shaft; and a second gear group including a plurality of second gears that transmit, to an output side, rotation of the second shaft transmitted from the first shaft. A first second gear is situated closest to the second shaft among the plurality of second gears, a last second gear is situated closest to the output side among the plurality of second gears. A straight line that connects a rotation center of the first second gear and a rotation center of the last second gear form an angle with the first shaft when viewed in a direction along the second shaft.