A motion assistance apparatus (10, 11, 12, 13, 13', 14) comprising: a fixing member configured to be fixed to a user; and a driving module (90, 100, 200, 300, 300', 400) provided on one side of the fixing member, the driving module (90, 100, 200, 300, 300', 400) comprising: a driving source (920, 120, 220, 320, 420) configured to transmit power; an input side rotary body (930, 130, 230, 330, 330', 430) connected to the driving source (920, 120, 220, 320, 420) and configured to rotate; and a first decelerator (940, 140, 240, 340, 440) and a second decelerator (960, 160, 260, 360, 460) configured to operate using the power received from the driving source (920, 120, 220, 320, 420) through the input side rotary body (930, 130, 230, 330, 330', 430), wherein a gear ratio from the input side rotary body (930, 130, 230, 330, 330', 430) to the output terminal of the first decelerator (940, 140, 240, 340, 440) differs from a gear ratio from the input side rotary body (930, 130, 230, 330, 330', 430) to the output terminal of the second decelerator (960, 160, 260, 360, 460), the motion assistance apparatus (10, 11, 12, 13, 13', 14) further comprising: a first joint member and a second joint member configured to assist respective rotary motions; a first power transmitting member connected to an output terminal of the first decelerator (940, 140, 240, 340, 440) to the first joint member such that the output terminal of the first decelerator (940, 140, 240, 340, 440) and the first joint member are enabled to have opposite rotation directions; and a second power transmitting member connected to an output terminal of the second decelerator (960, 160, 260, 360, 460) to the second joint member such that the output terminal of the second decelerator (960, 160, 260, 360, 460) and the second joint member are enabled to have identical rotation directions. a fixing member configured to be fixed to a user; and a driving module (90, 100, 200, 300, 300', 400) provided on one side of the fixing member, the driving module (90, 100, 200, 300, 300', 400) comprising: a driving source (920, 120, 220, 320, 420) configured to transmit power; an input side rotary body (930, 130, 230, 330, 330', 430) connected to the driving source (920, 120, 220, 320, 420) and configured to rotate; and a first decelerator (940, 140, 240, 340, 440) and a second decelerator (960, 160, 260, 360, 460) configured to operate using the power received from the driving source (920, 120, 220, 320, 420) through the input side rotary body (930, 130, 230, 330, 330', 430), a driving source (920, 120, 220, 320, 420) configured to transmit power; an input side rotary body (930, 130, 230, 330, 330', 430) connected to the driving source (920, 120, 220, 320, 420) and configured to rotate; and a first decelerator (940, 140, 240, 340, 440) and a second decelerator (960, 160, 260, 360, 460) configured to operate using the power received from the driving source (920, 120, 220, 320, 420) through the input side rotary body (930, 130, 230, 330, 330', 430), wherein a gear ratio from the input side rotary body (930, 130, 230, 330, 330', 430) to the output terminal of the first decelerator (940, 140, 240, 340, 440) differs from a gear ratio from the input side rotary body (930, 130, 230, 330, 330', 430) to the output terminal of the second decelerator (960, 160, 260, 360, 460), the motion assistance apparatus (10, 11, 12, 13, 13', 14) further comprising: a first joint member and a second joint member configured to assist respective rotary motions; a first power transmitting member connected to an output terminal of the first decelerator (940, 140, 240, 340, 440) to the first joint member such that the output terminal of the first decelerator (940, 140, 240, 340, 440) and the first joint member are enabled to have opposite rotation directions; and a second power transmitting member connected to an output terminal of the second decelerator (960, 160, 260, 360, 460) to the second joint member such that the output terminal of the second decelerator (960, 160, 260, 360, 460) and the second joint member are enabled to have identical rotation directions. a first joint member and a second joint member configured to assist respective rotary motions; a first power transmitting member connected to an output terminal of the first decelerator (940, 140, 240, 340, 440) to the first joint member such that the output terminal of the first decelerator (940, 140, 240, 340, 440) and the first joint member are enabled to have opposite rotation directions; and a second power transmitting member connected to an output terminal of the second decelerator (960, 160, 260, 360, 460) to the second joint member such that the output terminal of the second decelerator (960, 160, 260, 360, 460) and the second joint member are enabled to have identical rotation directions.