To provide an oscillation device which is not affected at all by a power source voltage or external noise in changing an output oscillation frequency by application of the voltage from the external, and a discharge tube lighting device with which a discharge tube can be lighted by a constant lighting current.

An oscillation device is provided with an oscillation frequency number control circuit B to change an oscillation frequency by controlling change/discharge of a capacitor 5 in a half cycle of the oscillation frequency determined by charge/discharge of the capacitor 5. This oscillation device is applied to a discharge tube lighting device, so a lighting current of a discharge tube is set constant by application of a voltage based on the lighting current of the discharge tube as a control voltage to the frequency oscillation control circuit B.