We present a novel approach to construct 3-D rotary micromirrors, which are fundamental components in optical switching systems. A rotary micromirror consists of two microparts: a rotary micromotor and a micromirror. Both of the two microparts are fabricated with PolyMUMPs,™ (MEMSCAP, Research Triangle Park, North Carolina), a surface micromachining process. A sequential robotic microassembly process is developed to join the two microparts together to construct the 3-D device. To achieve high positioning accuracy and strong mechanical connection, the micromirror is joined to the micromotor using an adhesive mechanical fastener. The mechanical microjoint has self-alignment capability and provides a temporary joint between the two microparts. The adhesive bonding creates a strong permanent connection between the two microparts. The adhesive mechanical fastener does not require extra supporting plates to fix the micromirror, which simplifies the microassembly process and makes it possible to automatically assemble the rotary micromirror. A hybrid manipulation strategy, which includes pick-and-place and pushing-based micromanipulations, is utilized to assemble the micromirror onto the micromotor. The pick-and-place manipulation has the ability to globally position the micromirror with multiple degrees of freedom. The pushing-based manipulation can achieve high positioning accuracy. This novel approach provides great flexibility and high accuracy for assembling the complex micromirror.