[en] In order to measure loading and residual stresses near the notch tip in Al₂O₃ ceramics using a micro X-ray beam of SPring 8 (Super Photon ring-8 GeV), X-ray elastic constants were first determined experimentally. Mechanical elastic constants of the used material were E=372 GPa and v=0.23. The diffraction from Al₂O₃ 2.0.14 plane by 8 keV radiation was used for X-ray stress measurement. The 2θ-sin²ψ diagrams under several applied stresses were measured. From the relationship between both slope, M, and intercept 2θ_ψ=0 of 2θ-sin²ψ diagram and applied stress, X-ray elastic constants were determined to be Ex=416 GPa and v_X=0.20. Next, the local stress measurement in the irradiated area with 100x100 μm² was examined in comparison to that with 100x500 μm². Loading stress in a local area with 100x100 μm² can be measured by the sin²ψ method. Finally, the local loading stresses, σ_y(x), near the V-notch tip under a four-point bending load were measured across the minimum ligament of SEVNB (Single-Edge-V-notched Beam) specimen by scanning the micro X-ray beam along the x-axis. The stress concentration near the notch root was first difficult to be measured directly because of the grinding residual stress by V-notch machining. After annealing, the stress concentration was detected by changing the irradiated area of X-ray from 100x100 to 50x50 μm². The degradation of the measured stresses in the notch tip was caused by the X-ray irradiation to the notch, and almost agreed with the results of a finite element analysis. The local stress and residual stresses were found to be measured by the sin²ψ method using synchrotron micro X-ray beam with a spatial resolution of about 50 μm. (author)