The present invention aims at providing: a sugar derivative capable of producing a blue fluorescent col-or, which can be used for the imaging of a cell or an intracellular molecule and a method for imaging a cell using the derivative. The present invention also aims at providing: a method for detecting a cancer cell with high accuracy by means of imaging and an imaging agent for use in the method. The present invention provides: a fluorescence-labeled sugar derivative having, in the molecule thereof, 3-carboxy-6,8-difluoro-7-hydroxycoumarin or 3-carboxymethyl-6,8-di-fluoro-7-hydroxy-4-methylcoumarin as a fluorescent molecular group and an imaging agent for a cell and a method for imaging a cell, in each of which the derivative is used. The present invention also provides an imaging agent for a cancer cell and a method for imaging a cancer cell, in each of which an L-glucose derivative having, in the molecule thereof, the fluorescent molecular group is used.
