A HGA includes a slider, a micro-actuator horizontally rotating the slider with a central portion of the slider as a rotation center, and a suspension to load the slider and the micro-actuator; wherein the micro-actuator comprises a support frame having a base, a moving plate, and a leading beam to connect the base and the moving plate; and at least one piezoelectric pieces to be connected with the base and the moving plate; wherein the leading beam has a pivot part to assist the horizontal swing of the slider. The pivot part has a narrower width than that of the leading beam. The suspension also includes a support means to support the base of the support frame on a suspension tongue portion. The invention also discloses a disk drive unit having the HGA.