Micrometeoroid detection in space usually involves high-velocity impact phenomena. In-situ dust detectors should be calibrated by a microparticle accelerator with a mass and velocity range comparable to micrometeoroids. A pilot model of an accelerator was constructed some years ago and fundamental research for an advanced facility has been performed. We are developing two new accelerators. A 3.75MV Van de Graaff electrostatic accelerator at The Research Center for Nuclear Science and Technology, University of Tokyo, has been modified to accelerate microparticles, and acceleration testing is now being carried out. The expected velocity range is 1-20 km/s for micron or sub-micron particles. Another small accelerator will be installed for easier handling, more frequent use, and lower-cost operation.