The invention relates to an antibody which binds to myelin oligodendrocyte glycoprotein (MOG), an antibody fragment thereof, a hybridoma which produces the antibody or the antibody fragment, a nucleic acid containing a nucleotide sequence which encodes the antibody or the antibody fragment, a transformant cell containing a vector containing the nucleic acid, a method for producing the antibody or the antibody fragment, a composition containing the antibody or the antibody fragment and a method for detecting or measuring an antigen that is present in the brain, a method for diagnosing or treating a brain disease, a method for improving the property of an antibody of accumulating in the brain and a method for increasing the amount of an antibody in the brain which use the antibody or the antibody fragment.
