PROBLEM TO BE SOLVED: To provide a compound useful for diagnosis of prostatic diseases and-related diseases such as prostate cancer.SOLUTION: The present invention provides a prostate specific membrane antigen (PSMA)-binding compound, represented by the following formula, wherein a ligand of a specific PSMA is linked to an imaging agent selected from the group consisting of fluorescein, AlexaFluor 647, DyLight 680, DyLight 800, and CW800 via a linker.SELECTED DRAWING: None