An electric bicycle is provided that can increase the diameter of the joining section between a crankshaft and a crank arm, suppress an increase in manufacturing cost, and minimize a size increase of a hanger with a torque sensor disposed in the hanger. A crankshaft 17 is divided into a crankshaft body 17A on the periphery of which a torque sensor 23 is disposed, and an auxiliary crankshaft 17B connected to one side of the crankshaft body 17A. A diameter D1 of the joining section between the auxiliary crankshaft 17B and a crank arm 18B and a diameter D3 of the joining section between the crankshaft body 17A and a crank arm 18A are larger than a diameter D2 of the connecting section between the crankshaft body 17A and the auxiliary crankshaft 17B.