An objective lens actuator in an optical pickup, having a semiconductor laser diode, electro-optic parts, such as a lens or the like, as well as, the objective lens actuator, etc., in a case, comprises: a holder, which mounts an objective lens and a coil thereon, as being a movable part; a magnetic circuit part, which is made up with a magnet for magnetically driving said holder and a yoke; a plural number of elastic support parts which elastically supports said holder; and a support part, which supports other ends of said elastic support parts, wherein said support part has a part, which is cut open in parallel with the elastic support parts, between said elastic support parts, and has a through hole, in which said elastic support part passes through for each of said elastic support parts, and thereby to provide the objective lens actuator for lowering the unwanted vibration mode of the objective lens, and also enabling a stable control thereof.