A novel fluorescent compound having a high light fastness, high fluorescence quantum yield and sharp absorption spectrum, which emits fluorescence having a wavelength in long wavelength region, as well as its use as a labeling agent, is disclosed. In Formula [I] below, by forming a specific hetero ring(s) with R1 and R2, and/or R6 and R7, shift of the wavelength of the fluorescence to longer wavelength and increase in molar extinction coefficient are attained maintaining the high light fastness, high fluorescence quantum yield and sharp absorption spectrum which the fluorescent dyes having the boron dipyrromethene skeleton have.