Using the CCT specimen made by an aluminum plate, the effect of anisotropy on the fatigue crack propagation path was investigated, and also the crack propagation path in semicircular notched plate was estimated. The obtained results were as follows. A marked effect of anisotropy appeared in the specimen whose rolling direction was inclined 15 or 30 degrees from the loading direction. Namely, in this case, all the cracks in plate specimens propagate along the rolling direction. However, in the other case, the cracks propagate along the Mode I direction. These results are considered to be based on the effect of Mode II crack propagation. In order to predict the crack propagation path under complicated stress conditions with FEM, the authors assume a condition in which the crack propagates along the rolling direction in the case of GII/GI≥2.0 and GI >GI th. If the above conditions are not satisfied, the crack propagates along the Mode I or maximum energy release rate direction. This assumption is proved by the crack propagation path of several types of semicircular notched plate specimens.