An electrically assisted bicycle is provided with a so-called single-shaft motor drive unit that can satisfactorily keep torque detection capability. The outer periphery of a crankshaft 7a has a cylindrical human-power transmission member 28 having a torque sensor 31 for detecting a human driving force and a combined force member 29 that combines a human driving force and an auxiliary driving force from a motor 21. A one-way clutch is not provided on a driving force transmission path including the crankshaft 7a, the human-power transmission member 28, and the combined force member 28. The human-power transmission member 28 and the combined force member 29 are always rotated in response to a rotation of the crankshaft 7a.