A lighting circuit includes a voltage converter configured to receive a DC voltage to perform voltage conversion and supply a drive current to a light source unit including a light emitting element, a bypass switch configured to form a bypass path through which the drive current bypasses the light emitting element, and a controller configured to control the voltage converter and the bypass switch. The light source unit includes a plurality of light emitting elements connected in series. The bypass path includes at least one bypass switch which are connected in parallel with at least one of the light emitting elements. When turning on the light emitting element of the light source unit, the controller controls the voltage conversion to start in a state where the bypass switch is turned on, and then, turns off the bypass switch to turn on the light emitting element.