Provided is a folding electric bicycle comprising a front frame section; a rear frame section comprising two bent arms individually having one end pivotably coupled to an axle passed rear wheel, and two auxiliary wheels rotatably mounted in open ends of the bent arms; a crossbar comprising a front end and a rear end pivotably coupled to the front and rear frame sections respectively; a latch detachably interconnected the crossbar and the rear frame section; and a down tube interconnected the front and rear frame sections. The rear frame section can either retract toward the front frame section about the unfastened latch for folding or extend from the front frame section about the unfastened latch for extending. The auxiliary wheels are either disposed above the ground when the bicycle is ready or rotatable and contact with the ground when the bicycle is folded for facilitating moving.