A speed reducer group is disclosed. The speed reducer group comprises: a first speed reducer which has a first crank assembly for oscillating a first oscillation gear to rotate a first output part around a first main shaft by performing rotation around a first transfer shaft separated from the first main shaft prescribed as the rotation center shaft of the first output part by a first distance; and a second speed reducer which has a second crank assembly for oscillating a second oscillation gear to rotate a second output part around a second main shaft by performing rotation around a second transfer shaft separated from the second main shaft prescribed as the rotation center shaft of the second output shaft by a second distance different from the first distance. Therefore, the present invention enables the manufacture of the speed reducer group even if a small amount of bearings is used.