The invention provides a piezoelectric actuator, a lens barrel, and an imaging device. The piezoelectric actuator includes a first piezoelectric element that performs thickness-shear vibration in a first direction, a first member that is driven by the first piezoelectric element and that vibrates in the first direction, a second piezoelectric element that is supported by the first member and that performs thickness-shear vibration in a second direction, a second member that is driven by the second piezoelectric element and that vibrates in the second direction, a pressurizing section that generates a pressure between the second member and a driving target member driven by the second member. The pressurizing section includes a third piezoelectric element that changes the pressure between the second member and a driving target member on the basis of a driving state of the driving target member.