A compound represented by the formula (I) [R1 represents hydrogen atom or a substituent; R2, R3, R6, and R7 represent hydrogen atom, an alkyl group, a halogen atom, or a hydrophilic substituent; R4 and R5 represent an alkyl group or an aryl group; R8 and R9 represent a group cleaved by contact with an object substance for measurement; and X represents silicon atom, germanium atom, or tin atom] or a salt thereof, which is useful as a fluorescent probe that emits red fluorescence by contact with an object substance for measurement.