A micro device having a micro system structure includes a protection film disposed on the micro system structure for protecting from a particle. The protection film includes a first protection film having a Vickers hardness equal to or larger than 2500 Hv or a nano indentation hardness equal to or larger than 13.64 GPa. The first protection film has a thickness in a range between 0.1 .mu.m and 30 .mu.m. The protection film has a total stress defined as a product of a film stress and a film thickness, and the total stress is equal to or smaller than 700 N/m.