Sb2O3 microrods with orthorhombic phase were grown by an evaporation-deposition method from a pure antimony source and substrate. The incorporation of Cr into the substrate has been found to enhance the growth of thinner rods with high crystalline quality, as is revealed by high resolution transmission electron microscopy (HRTEM). Electric field-induced mechanical resonances of Sb2O3 nanorods were studied by in situ measurements in a scanning electron microscope (SEM). Young's modulus of rods with different lengths and cross-sectional dimensions was calculated from the resonance frequency. The E values for the different rods were in the range of 16-48 GPa. For comparison, Young's moduli of several rods were also measured from the force-displacement curve recorded in an atomic force microscope (AFM). The slight difference between the E values obtained by the resonance and by the AFM techniques is within the accepted experimental error.