Microactuator,head gimbal assembly, and magnetic disk drive

Embodiments of the present invention help to suppress reduction of the operation quantity of a microactuator. According to one embodiment, a microactuator comprises a silicon substrate and a piezoelectric element. The silicon substrate has some rigidity and provides elastic counter force to the piezoelectric element. In the piezoelectric element a secondary piezoelectric layer is laminated on a primary piezoelectric layer opposite from the silicon substrate. The contraction force of the secondary piezoelectric layer acts on the primary piezoelectric layer so that it bends toward the secondary piezoelectric layer opposite from the silicon substrate. When the primary piezoelectric layer expands, the contraction force of the secondary piezoelectric layer acts on the primary piezoelectric layer so that it warps against the primary piezoelectric layer.