A PZT micro-actuator for a head gimbal assembly includes a pair of separate PZT elements and each PZT element has a body and a plurality of electrical pads. The body has at least two electrode-piezoelectric combination layers laminated together. The at least two electrode-piezoelectric combination layers are physically connected with but electrically isolated from each other. Each electrode-piezoelectric combination layer has at least two of the electrical pads thereon. The electrical pads extend out from the body of the corresponding PZT element. All the electrical pads of each PZT element are offset a predetermined distance therebetween to be electrically isolated. The present invention also discloses a head gimbal assembly (HGA) with the PZT micro-actuator, an assembling method for the head gimbal assembly and a disk drive unit having such HGA.