A gear apparatus includes a spur gear (66) including teeth(67) and to be rotated around a rotation axis, a rotation mechanism (44) to rotate the spur gear (66), a limitation member (90) including tooth (91.) to be engaged with the teeth (67) of the spur gear (66), the limitation member (90) to limit the rotation of the spur gear (66), a movement mechanism (76, 84, 88) to move the limitation member (90) in the radial direction of the rotation axis such that the tooth (91) of the limitation member (90) is engaged with the teeth (67) of the spur gear (66), an input mechanism (78) to input power to actuate the movement mechanism (76, 84, 88), a transmission mechanism (101) to transmit the power input by the input mechanism (78) to the movement mechanism (76, 84, 88), and an accumulation mechanism (101) provided in the transmission mechanism (101) and to accumulate the power input by the input mechanism (78) when a tip of the tooth (91) of the limitation member (90) contacts a tip of the tooth (67) of the spur gear (66).
