In order to investigate the mechanical factors dominating crack propagation induced by nano-meter-scale singular stress field, crack propagation experiments are carried out using silicon (Si) single crystal specimens, which possess precracks with nano-meter-scale singular stress field. The minimum size of singular stress field among specimens is 65 nm. Critical value of stress intensity factor at fracture, K_<IC>, is evaluated to be 1.05〜1.30 MPa・m^<1/2>. The result indicates that the fracture mechanics concept based on continuum mechanics is still valid.