This paper deals with the significance of the crack exisitng in the stress concentrated region from a view point of brittle fracture. The relation between the J -integral of the cracks existing in the stress concentrated regions and the local strain is investigated experimentally and theoretically with the aid of elasticplastic finite element analysis. The finite element analysis and test results lead to the following conclusions : (1) A non-dimensionalised J , JE / (σ _Y ² a ), computed in a plane stress condition for several kinds of stress concentrated regions with a short crack under tension gives a reasonably compact group of data, when plotted against the averaged strain across the assumed cracked area, e . The upper bound of a J design curve is defined as follows : JE / (σ _Y ² a )=4 ( e / e_Y ) ² for e / e_Y <1 JE / (σ _Y ² a )=4 ( e / e_Y ) for e / e_Y ≥1 where E : Young's modulus, σ _Y : yield stress a : half length of crack, e_Y : yield strain (=σ _Y / E ) (2) Use of this curve provides a good estimation for the brittle fracture from a crack existing in the stress and strain concentrated region.