The present invention relates to: an antibody capable of binding to myelin oligodendrocyte glycoprotein (MOG) or an antibody fragment thereof； a hybridoma capable of producing the antibody or the antibody fragment； a nucleic acid comprising a nucleotide sequence encoding the antibody or the antibody fragment； a transformant cell containing a vector carrying 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 occurring in brain, a method for diagnosing or treating a brain disease, a method for improving the accumulation of an antibody in brain, and a method for increasing the amount of an antibody in brain, in each of which the antibody or the antibody fragment is used.
