A through-thickness center-cracked specimen of fully annealed copper was cyclically deformed under a load-controlled condition. Then cyclic stress-strain response in the vicinity of the crack tip and the crack tip opening displacement were calculated using the elastic-plastic finite element method in which the constitutive equation derived on the basis of dislocation dynamics is used. The distributions of the axial and shear strains along with changes in them and in the crack tip opening displacement during each half of a load cycle were calculated ; the results corresponded well with the measurements. In addition, the calculated stress-strain response showed that the axial strain range and the mean strain decreased to a much greater extent closer to the crack tip as the cyclic loading process progressed.