The object of the present invention is to provide methods for inhibiting proliferation of neural stem cells, an agent for inhibiting proliferation of neural stem cells, and methods for using the same. According to the method of the present invention, a galectin-1 inhibitor such as anti-galectin-1 antibody and/or an integrin .beta.1 inhibitor such as anti-integrin .beta.1 antibody is administered to a human or a vertebrate other than human for inhibiting proliferation of neural stem cells. This method can be used for treatment of nerve injury and nerve tumors.