A radioactive halogen-labeled phenyoxyaniline derivative represented by the following formula: wherein R1 represents a group such as an alkyl group; X1, X2, X3 and X4 represent each a hydrogen atom, an alkyl group, an alkoxy group, an alkoxy group carrying 11C introduced thereinto or a radioactive halogen atom, provided that at least one of X1, X2, X3 and X4 represents an alkoxy group carrying 11C introduced thereinto or a radioactive halogen atom; which is a compound useful as a PBR ligand having a high affinity and a high selectivity. In in vitro measurement of PBR, a PBR ligand having a high affinity and a high selectivity is labeled with a radioactive halogen nuclear species so as to enable the measurement of PBR in vivo with the use of means including not only PET but also SPECT. Thus, a compound which is useful in early diagnosing, preventing and treating diseases such as Alzheimer type dementia can be obtained.