Abstract: The present invention stabilizes a control signal for an element that supplies a drive current to a light-emitting element. According to the present invention, a drive device includes a switch element, a current-limiting element, a current-limiting element control unit, and a detection unit. The switch element is connected in series with a light-emitting element and transmits a drive current during a light-emitting period. The current-limiting element is connected in series with the switch element and limits the drive current to a set current value. The current-limiting element control unit generates a current control signal corresponding to the set current value and supplies the current control signal to a control terminal of the current limiting element. The detection unit detects a change in the current control signal during the light-emitting period and causes the current-limiting element control unit to adjust the current control signal.