Abstract: In a labor saving device for an electric and manual bicycle, a five-way joint of the bicycle includes a first driving bushing, a ratchet at the first driving bushing and connected to a rotating axle by an elastically activated first wedge, a large gear disc, such that the motive power of a chain is transmitted to the axle of a rear wheel, and a second driving bushing is sheathed to the first driving bushing, and the center hole of the second driving bushing is installed with a ratchet in a direction opposite to the first driving bushing, and coupled with the first driving bushing by an elastically activated second wedge during a rotation, and a transmission gear is installed on a lateral side and engaged with a driving gear on a motor axle, such that when the driving power of the motor drives the bicycle to move forward, the rotating second driving bushing will drive the first driving bushing with the large gear disc to rotate the axle of the rear wheel, and the axle with the left and right cranks will remain