This paper describes the resonant characteristics of polycrystalline SiC micro resonators. The $1{mu}m$ thick polycrystalline 3C-SiC cantilevers with different lengths were fabricated using a surface micromachining technique. Polycrystalline 3C-SiC micro resonators were actuated by piezoelectric element and their fundamental resonance was measured by a laser vibrometer in vacuum at room temperature. For the $100{sim}40{mu}m$ long cantilevers, the fundamental frequency appeared at $147.2kHz{sim}856.3kHz$. The $100{mu}m$ and $80{mu}m$ long cantilevers have second mode resonant frequency at 857.5.kHz and 1.14.MHz, respectively. Therefore, polycrystalline 3C-SiC resonators are suitable for RF MEMS devices and bio/chemical sensor applications.