A piezoelectric drive device includes a rotor which has an output section for outputting a rotational force and a transmission section disposed on an outer periphery of the output section, and rotates around a rotational axis, and a vibrating part which has a piezoelectric element, and rotates the rotor due to a deformation of the piezoelectric element. The transmission section has a first portion and a second portion different from each other in position in a radial direction from the output section toward the transmission section, the first portion is coupled to the output section, the second portion is higher in Young's modulus than the first portion, the second portion is higher in mass per unit volume than the first portion, and the vibrating part makes contact with the transmission section at a position overlapping the second portion in a plan view from an axial direction of the rotational axis.