This paper describes new polymer/ceramic photosensitive resins that can be used in the microstereolithography process for manufacturing complex 3D components in composite material. These new resins contain high loads (up to 80 wt.%) of alumina nanoparticles, used as fillers in a photosensitive acrylate-based resin of low viscosity. With the nanopowder-filled resin we developed, various small polymer/alumina composite components having a real geometric complexity were produced with small manufacturing times. When using a reactive medium containing a high enough percentage of ceramic nanoparticles, no deformation or cracks are observed after debinding and sintering, even if some shrinkage occurs during these steps. This process makes it possible to manufacture a new set of micro-components in ceramic material that could be of interest for high-temperature micro-reaction technologies, or for the production of new components in the biomedical domain.