The invention provides a driving device which is used together with a light source including a plurality of light emitting units connected in series to configure a vehicle lamp. The driving device includes a current source which is configure to supply a drive current to the light source, and N bypass circuits which are provided in parallel to N light emitting units, respectively. Each of the bypass circuits includes a bypass transistor which is provided in parallel to a corresponding light emitting unit, a feedback capacitor which is provided between a gate and a drain of the bypass transistor, and a gate drive circuit which is configured to supply a drive voltage between the gate and a source of the bypass transistor according to a control signal.