We have developed micro mechanical variable optical attenuators (VOA) using an electrostatic micro torsion mirror combined with fiber-optic collimators. For the sake of high productivity and high mechanical reliability, we have designed ASymmetricaly driven Parallel plate (ASP) Tilt Mirror (TM). The structure of ASP-type TM is very simple and it can be made by using bulk micromachining of SOI wafer. As a result, we have successfully downsized the VOA package to 5.6 mm in diameter and 23 mm in length. Optical performance is excellent for the optical communication network, small insertion loss of 0.8 dB and polarization dependent loss of 0.2 dB have been obtained.