A fluorescent gadolinium complex compound comprising a residue of gadolinium.1,4,7,10-tetraazacyclododecane-N,N′,N″,N′″-tetraacetic acid or a residue of gadolinium.diethylenetriaminepentaacetic acid bound covalently with a group represented by the following general formula (I) (R1 represents hydrogen atom or a substituent R2, R4, R5 and R7 represent hydrogen atom, a halogen atom or a C1-6 alkyl group, and R3 and R6 represent hydrogen atom, a halogen atom or a C1-6 alkyl group), which is easily taken up into cells and useful as a probe observable by the fluorescence method and MRI.