Uniaxial tensile testing for single crystal silicon (SCS) films was conducted to investigate the fracture mechanism of silicon. The loading axis of the SCS specimens had three main crystallographic orientations, that is <100>, <110>, and <111>, fabricated from one (110) silicon-on-insulator wafer. The dimensions of specimen test part were 10 μm wide, 5 μm thick, and 120 μm long having 1 μm-depth notch at the center. The measured average fracture force of <100>, <110>, and <111> specimens was 44.2, 53.5, and 45.8 mN, respectively. The difference in fracture force between <110> and <111> specimens was well elucidated with the normal stress for (111) cleavage plane using Weibull statistics considering the stress distribution on notch surface and existence of multiple cleavage planes in SCS.