A method of manufacturing a fluorescent lamp is provided. One of a dispersed metal oxide precursor sol prepared by a sol-gel reaction and a fluorescent substance slurry is coated on a glass tube having at least one open side and then the other of the fluorescent substance slurry and the dispersed metal oxide precursor sol is coated on the glass tube. Next, passivation and fluorescent layers are simultaneously formed by baking the coated layers. Then, air is exhausted out of the glass tube and a discharge gas is injected into the glass tube. Finally, the glass tube is sealed.