MEMS technology is fast becoming the new enabling technology for areas that require the performance and cost advantages it brings. In this paper, as one of its promising application areas, MEMS technology for a ultra small optical pickup module is presented. The optical flying head is constructed by integration of micromachined devices such as micro slider, micro coil, microactuator, and micro lens within 0.5 mm in height. The basic optical unit comprised of refractive and diffractive optical elements including LD, PD, polarizers, and collimating lens is built by wafer level stacking within its dimension of 3.0/spl times/3.0/spl times/5.5 mm/sup 3/. By assembling of the optical flying head and the basic optical unit onto a swing arm, it is possible to obtain an ultra small pickup system which can be applied in mobile environment.