A method for measuring an adhesion strength of a resin material which is capable of accurately and readily measuring a universal adhesion strength independent of dimensions and shapes of specimen. A delamination portion is partially formed between a resin and an adherend material. Loads in two different directions are applied to an adhering interface such that opposed shear stresses are generated. As a result, a true adhering strength can be obtained from an apparent delamination propagating strength in each case.