A lesion detecting method and a lesion detecting apparatus for breast image in a rotating manner are provided. In the method, a set of breast image in the rotating manner is obtained. The set of breast image in the rotating manner contains sub breast images. The sub breast image is reconstructed, to generate a reconstructed breast image. The reconstructed breast image is compared with the set of breast image in the rotating manner without being reconstructed. Accordingly, at least one lesion position would be confirmed according to the comparing result. Therefore, viewing a three-dimensional breast image would be convenient for medical staff, and false positive of detecting lesion would be reduced.