Abstract: There is disclosed an oscillator circuit for driving a fluorescent lamp, which comprises a power transistor having an emitter electrode connected to one terminal of a D.C. power source and a collector electrode connected to the other terminal of the D.C. power source through a primary winding of a transformer. A first secondary winding of the transformer is connected at its one end to the other terminal of the D.C. power source and at its other end to a base electrode of the transistor through one of a pair of filaments of the fluorescent lamp. A second secondary winding of the transformer is connected at its one end to the one filament of the fluorescent lamp and at its other end to the other filament of the fluorescent lamp to cause discharge in the fluorescent lamp.