A compound effective as a probe targeting amyloid for image diagnosis and a reagent comprising the compound for detecting amyloid deposited on a biological tissue are provided. Provided are a compound represented by the following formula (1): wherein R1 is a group selected from the group consisting of a halogen substituent, alkyl substituent with 1 to 4 carbon atoms, alkoxy substituent having alkyl chain with 1 to 4 carbon atoms and hydroxyl group, R2 is a group selected from the group consisting of a cyano substituent, alkyl substituent with 1 to 4 carbon atoms and halogen substituent, R3 is a group selected from the group consisting of a hydroxyl group, halogen substituent and substituent represented by the following formula: (wherein R4 is a hydrogen, halogen substituent or hydroxyl group, and m is an integer of 1 to 4), provided that at least one of R1, R2, R3 and R4 represents a radioactive halogen, and a reagent comprising the same.