A process for the production of [.sup.18F]fluoro-2-deoxyglucose can produce [.sup.18F]fluoro-2-deoxyglucose in a high and stable yield of synthesis. A process for the production of a compound labeled with radioactive fluorine includes the preparing a reaction solution by adding, under a hermetic condition, TATM and an inert organic solvent to a mixture containing [.sup.18F]fluoride ions, a phase transfer catalyst and potassium ions, giving a reaction condition to the reaction solution under a hermetic condition to obtain [.sup.18F]-TAFDG, and subjecting the obtained [.sup.18F]fluoro-2-deoxyglucose to a deprotection process and, optionally, to a purification process to obtain [.sup.18F]fluoro-2-deoxyglucose.