A micro-actuator includes a metal frame having two side arms, a top support arm and a bottom support arm respectively connected with the top ends of the two side arms. The two side arms are in parallel with and spaced from each other a distance adapted to hold a slider therebetween that is mounted on the top support arm. An isolation layer is coupled with each side arm of the metal frame; and a piezoelectric element is bonded with the isolation layer. When operating the micro-actuator, an electric sparking problem will not occur for existence of the isolation layer. The invention also disclose a method of manufacturing the micro-actuator, a HGA and disk drive unit with the micro-actuator.